Preparation method of graphene high-temperature heating sheet

Abstract

The application discloses a preparation method of a graphene high-temperature heating sheet and relates to a preparation method of a high-temperature heating sheet.The application aims at solving the problem that the existing graphene heating sheet cannot realize a heating temperature above 100 DEG C.The preparation method comprises the following steps: one, preparing a graphene high-temperature ink; and two, preparing a graphene high-temperature heating sheet.The application is used for the preparation of the graphene high-temperature heating sheet.

Description

Technical Field

[0001] This invention relates to a method for preparing a high-temperature heating element. Background Technology

[0002] Energy is the foundation for human survival and development. With the rapid development of science and technology, people's demand for energy is increasing, as is the demand for energy conservation. Ordinary high-temperature heaters, due to their high energy consumption, can no longer meet the energy-saving requirements of modern equipment. Graphene has excellent electrical conductivity and, due to its rapid heating speed and high electrothermal conversion efficiency, has been widely used in various low-pressure physiotherapy products, insulation products, building heating, and device heating. Its heating temperature is generally between 50℃ and 100℃, mainly used to meet people's low-temperature needs in daily life. However, graphene high-temperature heating elements with temperatures above 100℃ or even higher have not yet been reported. Summary of the Invention

[0003] The present invention aims to solve the problem that existing graphene heating sheets cannot achieve heating temperatures above 100°C, and thus provides a method for preparing a high-temperature graphene heating sheet.

[0004] A method for preparing a graphene high-temperature heating plate, comprising the following steps:

[0005] I. Preparation of graphene high-temperature ink:

[0006] ① Using graphene as raw material, polyvinylpyrrolidone is added as a surfactant and water is added as a dispersant. The mixture is then ultrasonically dispersed to obtain a graphene slurry.

[0007] The graphene is physically produced graphene; the mass ratio of graphene to polyvinylpyrrolidone in the graphene slurry is (7-20):1.

[0008] ② Add aluminum dihydrogen phosphate solution and magnesium oxide to graphene slurry, and then disperse it using a high-speed disperser, homogenize it using a high-pressure homogenizer, and degas it using a degassing machine in sequence to obtain graphene high-temperature ink;

[0009] The aluminum dihydrogen phosphate solution has a mass ratio of aluminum dihydrogen phosphate to magnesium oxide of 1:(0.1-1); the graphene accounts for 15%-20% of the total mass of graphene, polyvinylpyrrolidone, aluminum dihydrogen phosphate, and magnesium oxide; the graphene in the graphene high-temperature ink has a mass percentage of 3%-9%; and the viscosity of the graphene high-temperature ink is 10000 CPS-20000 CPS.

[0010] II. Preparation of graphene high-temperature heating plates:

[0011] Graphene high-temperature ink is printed onto a substrate, dried, then annealed, and finally electrodes are added to obtain a graphene high-temperature heating plate.

[0012] The beneficial effects of this invention are:

[0013] 1. Using inorganic materials as a binder has the function of isolating oxygen and resisting oxidation. During use, it will form an insulating film with a self-protective effect, and is suitable for heating under high temperature conditions.

[0014] 2. Aluminum dihydrogen phosphate is used as a binder, enabling the graphene high-temperature ink to withstand high temperatures of 500℃~1000℃.

[0015] 3. High-speed disperser, high-pressure homogenizer, and degassing machine are used to disperse the graphene high-temperature ink, making the resulting ink more uniformly dispersed.

[0016] 4. Using high-temperature resistant quartz glass as the substrate and conductive silver paste as the electrode, the resulting graphene high-temperature heater has good thermal cycling performance (durability test reaches 30,000 hours, power change ≤1% after 10,000 high and low temperature cycles, and power change ≤10% after 100,000 high and low temperature cycles).

[0017] Instruction manual illustrations

[0018] Figure 1 The image shows the actual graphene high-temperature heating sheet prepared in Example 1. 1 is the graphene high-temperature ink prepared in step 1 of Example 1, 2 is black microcrystalline glass, and 3 is conductive silver paste.

[0019] Figure 2 For comparison, a graphene high-temperature heating sheet without electrodes was heated at 600℃ for 24 hours.

[0020] Figure 3 This is a photograph of the graphene high-temperature heating sheet without electrodes in Example 1 after heating at 600°C for 24 hours.

[0021] Figure 4 An infrared thermometer photograph of the heating process of the graphene high-temperature heating sheet prepared in Example 1;

[0022] Figure 5 The images shown are of the graphene high-temperature ink degassing machine before and after degassing in step 1 of Example 1, a. before degassing, b. after degassing.

[0023] Figure 6 This is a photograph of the graphene high-temperature heating sheet prepared in Example 1 after being heated for 30,000 hours at a temperature of 250°C.

[0024] Figure 7This is a graphene particle size distribution diagram as described in step 1① of Example 1. Detailed Implementation

[0025] Specific Implementation Method 1: This implementation method describes a method for preparing a graphene high-temperature heating plate, which is carried out according to the following steps:

[0026] I. Preparation of graphene high-temperature ink:

[0027] ① Using graphene as raw material, polyvinylpyrrolidone is added as a surfactant and water is added as a dispersant. The mixture is then ultrasonically dispersed to obtain a graphene slurry.

[0028] The graphene is physically produced graphene; the mass ratio of graphene to polyvinylpyrrolidone in the graphene slurry is (7-20):1.

[0029] ② Add aluminum dihydrogen phosphate solution and magnesium oxide to graphene slurry, and then disperse it using a high-speed disperser, homogenize it using a high-pressure homogenizer, and degas it using a degassing machine in sequence to obtain graphene high-temperature ink;

[0030] The aluminum dihydrogen phosphate solution has a mass ratio of aluminum dihydrogen phosphate to magnesium oxide of 1:(0.1-1); the graphene accounts for 15%-20% of the total mass of graphene, polyvinylpyrrolidone, aluminum dihydrogen phosphate, and magnesium oxide; the graphene in the graphene high-temperature ink has a mass percentage of 3%-9%; and the viscosity of the graphene high-temperature ink is 10000 CPS-20000 CPS.

[0031] II. Preparation of graphene high-temperature heating plates:

[0032] Graphene high-temperature ink is printed onto a substrate, dried, then annealed, and finally electrodes are added to obtain a graphene high-temperature heating plate.

[0033] This specific embodiment requires the use of physical methods to prepare graphite, resulting in low functional groups and oxidation levels. Graphene prepared by chemical redox methods has a high degree of oxidation, expands at high temperatures, and exhibits unstable oxidative chemical properties. The CVD method is too costly. A particle size requirement of 4-30 micrometers is necessary for better self-assembly.

[0034] In this specific embodiment, if the concentration of the aluminum dihydrogen phosphate solution is too high, aluminum dihydrogen phosphate will precipitate during the preparation process; if the concentration is too low, the viscosity will be low, the ink will be unstable, and graphene segregation will easily occur.

[0035] The beneficial effects of this embodiment are:

[0036] 1. Using inorganic materials as a binder has the function of isolating oxygen and resisting oxidation. During use, it will form an insulating film with a self-protective effect, and is suitable for heating under high temperature conditions.

[0037] 2. Aluminum dihydrogen phosphate is used as a binder, enabling the graphene high-temperature ink to withstand high temperatures of 500℃~1000℃.

[0038] 3. High-speed disperser, high-pressure homogenizer, and degassing machine are used to disperse the graphene high-temperature ink, making the resulting ink more uniformly dispersed.

[0039] 4. Using high-temperature resistant quartz glass as the substrate and conductive silver paste as the electrode, the resulting graphene high-temperature heater has good thermal cycling performance (durability test reaches 30,000 hours, power change ≤1% after 10,000 high and low temperature cycles, and power change ≤10% after 100,000 high and low temperature cycles).

[0040] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the ultrasonic dispersion described in step one ① is specifically ultrasonic dispersion for 0.5h to 4h under a power of 800W to 1500W. Everything else is the same as in Specific Implementation Method One.

[0041] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the graphene D50 mentioned in step one ① is 4 micrometers to 30 micrometers. Everything else is the same as in Specific Implementation Method One or Two.

[0042] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the high-speed disperser dispersion described in step one, ②, is specifically carried out at a rotation speed of 3000 rpm to 5000 rpm for 0.5 h to 1 h. Everything else is the same as in Specific Implementation Methods One to Three.

[0043] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the high-pressure homogenizer homogenization described in step one ② is specifically carried out at 350 bar to 2500 bar for 2 to 4 hours. Everything else is the same as in Specific Implementation Methods One to Four.

[0044] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the degassing process described in step one, ②, is specifically performed at a rotation speed of 900 r / min to 1200 r / min for 5 to 15 minutes. Everything else is the same as in Specific Implementation Methods One to Five.

[0045] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that the mass percentage of the aluminum dihydrogen phosphate solution mentioned in step one ② is 40% to 60%. Everything else is the same as in Specific Implementation Methods One to Six.

[0046] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that: the substrate described in step two is high-temperature resistant quartz glass; the electrode described in step two is graphene paper or conductive silver paste. Everything else is the same as in Specific Implementation Methods One to Seven.

[0047] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that: in step two, a screen printing process with a mesh size of 80 to 100 is used to print graphene high-temperature ink onto the substrate, resulting in a coating thickness of 10 μm to 50 μm after printing. Everything else is the same as in Specific Implementation Methods One to Eight.

[0048] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods One to Nine in that: the drying process in step two is specifically carried out at a temperature of 80℃ to 100℃ for 5 to 10 minutes; the annealing process in step two is specifically carried out at a temperature of 500℃ to 600℃ for 5 to 10 minutes. Everything else is the same as in Specific Implementation Methods One to Nine.

[0049] The beneficial effects of the present invention are verified using the following embodiments:

[0050] Example 1:

[0051] A method for preparing a graphene high-temperature heating plate, comprising the following steps:

[0052] I. Preparation of graphene high-temperature ink:

[0053] ① Using graphene as raw material, polyvinylpyrrolidone is added as a surfactant and water is added as a dispersant. The mixture is then ultrasonically dispersed to obtain a graphene slurry.

[0054] The graphene is physically produced graphene; the mass ratio of graphene to polyvinylpyrrolidone in the graphene slurry is 7:1.

[0055] ② Add aluminum dihydrogen phosphate solution and magnesium oxide to graphene slurry, and then disperse it using a high-speed disperser, homogenize it using a high-pressure homogenizer, and degas it using a degassing machine in sequence to obtain graphene high-temperature ink;

[0056] The aluminum dihydrogen phosphate solution has a mass ratio of aluminum dihydrogen phosphate to magnesium oxide of 1:0.1; the graphene accounts for 15% of the total mass of graphene, polyvinylpyrrolidone, aluminum dihydrogen phosphate and magnesium oxide; the graphene in the graphene high-temperature ink has a mass percentage of 3%; and the viscosity of the graphene high-temperature ink is 10000 CPS.

[0057] II. Preparation of graphene high-temperature heating plates:

[0058] Graphene high-temperature ink is printed onto a substrate, dried, then annealed, and finally electrodes are added to obtain a graphene high-temperature heating plate.

[0059] The ultrasonic dispersion mentioned in step 1① specifically refers to ultrasonic dispersion for 0.5 hours under a power of 800W.

[0060] The high-speed disperser dispersion mentioned in step 1② specifically refers to dispersion at a speed of 3000 rpm for 0.5 hours.

[0061] The high-pressure homogenizer homogenization mentioned in step 1② specifically refers to homogenization at 350 bar for 2 hours.

[0062] The degassing process described in step 1② specifically involves degassing for 5 minutes at a rotation speed of 900 r / min.

[0063] The mass percentage of the aluminum dihydrogen phosphate solution mentioned in step 1② is 54%.

[0064] The substrate described in step two is black microcrystalline glass (temperature resistance 1100℃) or light brown microcrystalline glass (temperature resistance 700℃); the electrode described in step two is conductive silver paste.

[0065] In step two, 80-mesh screen printing is used to print graphene high-temperature ink onto the substrate, resulting in a coating thickness of 10μm after printing.

[0066] The drying process described in step two is specifically drying at a temperature of 80°C for 5 minutes; the annealing process is specifically annealing at a temperature of 500°C for 5 minutes.

[0067] Example 2: This example differs from Example 1 in that: the mass ratio of graphene to polyvinylpyrrolidone in the graphene slurry described in step 1① is 10:1; the high-speed disperser dispersion described in step 1② is specifically dispersed at 5000 rpm for 1 hour; and the high-pressure homogenizer homogenization described in step 1② is specifically homogenized at 1400 bar for 4 hours. The degassing process described in Step 1② specifically involves degassing for 15 minutes at a speed of 1200 r / min; the graphene content in Step 1② comprises 20% of the total mass of graphene, polyvinylpyrrolidone, aluminum dihydrogen phosphate, and magnesium oxide; the graphene content in the high-temperature graphene ink described in Step 1② is 5% by mass; the viscosity of the high-temperature graphene ink described in Step 1② is 20000 CPS; in Step 2, the high-temperature graphene ink is printed onto the substrate using a 100-mesh screen printing process, resulting in a coating thickness of 50 μm; the drying process in Step 2 specifically involves drying at 100°C for 10 minutes; the annealing process specifically involves annealing at 600°C for 10 minutes. All other procedures are the same as in Example 1.

[0068] Example 3: This example differs from Example 1 in that: the mass ratio of graphene to polyvinylpyrrolidone in the graphene slurry described in step 1① is 16:1; the high-speed disperser dispersion described in step 1② is specifically carried out at a speed of 4000 rpm for 1 hour; and the high-pressure homogenizer homogenization described in step 1② is specifically carried out at 2500 bar for 3 hours. The degassing process described in Step 1② specifically involves degassing for 10 minutes at a speed of 1000 r / min; the graphene content in Step 1② comprises 20% of the total mass of graphene, polyvinylpyrrolidone, aluminum dihydrogen phosphate, and magnesium oxide; the graphene content in the high-temperature graphene ink described in Step 1② is 9% by mass; the viscosity of the high-temperature graphene ink is 15000 CPS; in Step 2, the high-temperature graphene ink is printed onto the substrate using a 100-mesh screen printing technique, resulting in a coating thickness of 30 μm; the drying process in Step 2 specifically involves drying at 100°C for 10 minutes; the annealing process specifically involves annealing at 550°C for 8 minutes. All other procedures are the same as in Example 1.

[0069] Comparative Experiment: This comparative experiment differs from Example 1 in that the graphene mentioned in step 1① is reduced graphene oxide. Everything else is the same as in Example 1.

[0070] Figure 1 The image shows the actual graphene high-temperature heating sheet prepared in Example 1. 1 is the graphene high-temperature ink prepared in step 1 of Example 1, 2 is black microcrystalline glass, and 3 is conductive silver paste.

[0071] Figure 2 For comparison, a graphene high-temperature heating sheet without electrodes was heated at 600℃ for 24 hours. Figure 3 This is a photograph of the graphene high-temperature heating sheet without electrodes from Example 1 after heating at 600°C for 24 hours; and Figure 2 and Figure 3 The substrate used in the experiment is light brown microcrystalline glass. As shown in the figure, the graphene high-temperature heating sheet prepared using redox graphene as raw material has burned out, while the graphene high-temperature heating sheet prepared using physical method as raw material has not burned out.

[0072] Figure 4 The image shows an infrared thermometer photograph of the graphene high-temperature heating sheet prepared in Example 1 during the heating process. As can be seen from the figure, the heating temperature of the graphene high-temperature heating sheet is 628°C under a voltage of 220V.

[0073] Figure 5 The images shown are actual pictures of the graphene high-temperature ink degassing machine before and after degassing in step 1② of Example 1. a is before degassing, and b is after degassing. As can be seen from the pictures, before degassing, the surface of the graphene high-temperature heating sheet is uneven and the graphene is not evenly dispersed. After degassing, the surface of the graphene high-temperature heating sheet is smooth and flat, which is conducive to the dispersion of graphene and the uniformity of heating temperature.

[0074] Figure 6 The image shows the graphene high-temperature heating sheet prepared in Example 1 after being heated for 30,000 hours at a temperature of 250°C. As can be seen from the image, the graphene high-temperature heating sheet did not change after being heated for 30,000 hours compared to before heating.

[0075] Power was applied at an ambient temperature of -20°C to raise the heating temperature of the graphene high-temperature heating element prepared in Example 1 to a set temperature of 250°C. Then the power was turned off and the element was cooled to an ambient temperature of -20°C. This cycle was repeated. The power change of the graphene high-temperature heating element prepared in Example 1 was ≤1% after 10,000 high and low temperature cycles and ≤10% after 100,000 high and low temperature cycles.

[0076] Figure 7 The graphene particle size distribution diagram is shown in step 1① of Example 1. As can be seen from the figure, the particle size of graphene is D10 = 1.631 μm, D50 = 7.796 μm, and D90 = 37.12 μm, and the particle size is close to a normal distribution.

Claims

1. A method of producing a graphene high-temperature heating sheet, characterized by It is carried out in the following steps: I. Preparation of graphene high temperature ink: ①, with graphene as raw material, adding polyvinylpyrrolidone as surfactant, adding water as dispersant, mixing and under the condition of power 800W-1500W, ultrasonic dispersion 0.5h-4h, get graphene slurry; The graphene is physical graphene; the mass ratio of graphene to polyvinylpyrrolidone in the graphene slurry is (7-20):1; the graphene D50 is 4-30 microns; ②, aluminum dihydrogen phosphate solution and magnesium oxide are added to the graphene slurry, then dispersed by high speed disperser, homogenized by high pressure homogenizer and defoamed by defoaming machine, to get graphene high temperature ink; The mass ratio of aluminum dihydrogen phosphate to magnesium oxide in the aluminum dihydrogen phosphate solution is 1:(0.1-1); the mass percentage of graphene in the total mass of graphene, polyvinylpyrrolidone, aluminum dihydrogen phosphate and magnesium oxide is 15%-20%; the mass percentage of graphene in the graphene high temperature ink is 3%-9%; the viscosity of the graphene high temperature ink is 10000CPS-20000CPS; the mass percentage of the aluminum dihydrogen phosphate solution is 40%-60%; The high speed disperser dispersing is specifically under the condition of 3000rpm-5000rpm, dispersing for 0.5h-1h; The high pressure homogenizer homogenizing is specifically under the condition of 350bar-2500bar, homogenizing for 2h-4h; The defoaming machine defoaming is specifically under the condition of 900r / min-1200r / min, defoaming for 5min-15min; II. Preparation of graphene high temperature heating sheet: Using silk screen printing with mesh number of 80-100 meshes, printing graphene high temperature ink on the substrate, after printing, the coating thickness is 10-50 microns, drying at a temperature of 80-100℃ for 5-10min, then annealing at a temperature of 500-600℃ for 5-10min, finally adding electrode, to get graphene high temperature heating sheet.

2. The method of claim 1, wherein the graphene high-temperature heating sheet is prepared by the steps of: The substrate in step two is high temperature resistant quartz glass; the electrode in step two is graphene paper or conductive silver paste. ​

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