Preparation method of nano-graphite flake composite material

Abstract

The invention discloses a preparation method of a nano graphite sheet composite material, which comprises the following specific steps: step 1, mounting a graphite plate at an anode of an electrolytic bath, and mounting a stainless steel sheet at a cathode of the electrolytic bath; and 2, electrolyte is poured into the electrolytic bath, so that the anode and the cathode are completely immersed by the electrolyte. The electrolyte is prepared by mixing the sulfuric acid and the phosphoric acid, sulfate ions in the sulfuric acid are high in capacity of being embedded between graphite layers and high in stripping efficiency, but graphite is prone to being excessively oxidized (a large number of oxygen-containing groups such as-COOH and-OH are generated), oxygen and sulfur dioxide gas can be generated, meanwhile, stripping between the layers can be promoted, and the performance of the electrolyte is improved. The intercalation capability of phosphoric acid ions of phosphoric acid is relatively weak, so that the breakage of a carbon skeleton can be reduced, and the acidity of phosphoric acid is relatively weak, so that the efficiency of oxidation reaction can be neutralized, and the excessive oxidation of graphite can be effectively reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of nano-graphite sheet composites, and specifically relates to a preparation method of nano-graphite sheet composites. Background Art

[0002] As monolayer graphite, also known as graphene, is a two-dimensional honeycomb lattice structure formed by tightly packing single-layer carbon atoms with graphite bonds (sp2), so it has a thickness of only one carbon atom. The graphite bond is a combined bond of covalent bond and metallic bond, which can be said to be a perfect combination of insulator and conductor. Nano-graphite sheets refer to graphene sheet layer structures with a thickness in the nanoscale (usually several to dozens of carbon atoms). They have unique physical and chemical properties and are a derivative or intermediate form of graphene. Nano-graphite sheets have high electrical conductivity, high thermal conductivity (close to graphene, but slightly decreasing with the increase of the number of layers), high mechanical strength, large specific surface area (up to hundreds of m2 / g), good chemical stability, and are easy to be functionalized and modified. However, there are some problems in the current preparation process of nano-graphite sheets: during the preparation of nano-graphite sheets, long-term electrolysis easily leads to excessive oxidation of the graphite sheets, resulting in most of the produced graphite sheets being graphite oxide, which affects the yield of nano-graphite sheets. Therefore, a preparation method of nano-graphite sheet composites needs to be designed. Summary of the Invention

[0003] The purpose of the present invention is to provide a preparation method of nano-graphite sheet composites to solve the above problems and those mentioned in the background art.

[0004] To solve the above problems, the present invention provides a technical solution for a preparation method of nano-graphite sheet composites as follows:

[0005] A preparation method of nano-graphite sheet composites includes the following specific steps:

[0006] Step 1: Install a graphite plate at the anode of the electrolytic cell and install a stainless steel sheet at the cathode of the electrolytic cell;

[0007] Step 2: Pour electrolyte into the interior of the electrolytic cell so that the electrolyte completely submerges the anode and the cathode;

[0008] Step 3: Apply a DC voltage to the anode, and bubbles are generated on the surface of the graphite plate at the anode. At the same time, electrolyte ions are embedded into the interlayer of the graphite, causing the graphite to expand;

[0009] Step 4: After the graphite layers of the graphite plate expand, they peel off, and the graphite layers disperse into the interior of the electrolyte to form a suspension;

[0010] Step 5: Filter the suspension in Step 4, and then wash the filtered solid matter with a cleaning solution;

[0011] Step 6: Put the solid obtained in Step 5 into the interior of a graphite drying furnace for high-temperature drying treatment. Place the washed solid into the interior of a drying crucible, then cover the outside of the graphite drying furnace with a sealed furnace lid, cover it tightly and screw the sealed furnace lid tightly. During the process of screwing the sealed furnace lid tightly, the sealed furnace lid squeezes the support bar and the scraping bar against the inner wall of the drying crucible through the central rotating shaft. At the same time, the support bar pushes the connecting plate upward. During the upward movement of the connecting plate, the spring can be compressed. After the spring is compressed, it generates an elastic force. The spring can push the scraping bar outside the support bar below the connecting plate against the inner wall of the drying crucible through the generated elastic force. Then start the constant-temperature electric heating tube. The heat generated by the constant-temperature electric heating tube can heat the solid inside through the drying crucible. At the same time, start the high-temperature resistant motor. The high-temperature resistant motor drives the central rotating shaft to rotate. The central rotating shaft drives the connecting nail to rotate around the central rotating shaft through the fixed frame. During the rotation of the connecting nail, it can drive the support bar and the scraping bar to rotate on the inner wall of the drying crucible through the connecting plate, and clean the solid adhered to the inner wall of the drying crucible, which can prevent the solid from adhering to the inner wall of the drying crucible and causing overheating. At the same time, the fixed objects inside the drying crucible can be disturbed through the support bar, which can make the heating of the solid more uniform. During the heating process, start the drainage fan. The drainage fan generates suction, and the suction can suck out the high-temperature water vapor inside the drying crucible. After being sucked out, the dry air flow can enter the interior of the drying crucible through the air inlet pipe. After heating for - hours, wait for the drying crucible to cool naturally, then take out the drying crucible from the interior of the graphite drying furnace and take out the solid, and then nano-graphite flakes can be obtained.

[0012] Preferably, the electrolyte in Step 2 is prepared by mixing sulfuric acid and phosphoric acid, and the ratio of sulfuric acid to phosphoric acid is 3:1.

[0013] Preferably, the electrolysis time in Step 3 is 40 - 50 minutes.

[0014] A preparation device for a nano-graphite flake composite material, including a graphite drying furnace. A drying crucible is slidably connected inside the graphite drying furnace. The upper end of the graphite drying furnace is threadedly connected with a sealed furnace lid. A constant-temperature electric heating tube is fixedly connected inside the inner wall of the graphite drying furnace. A central rotating shaft is installed inside the sealed furnace lid through a bearing. A fixed frame is fixedly connected to the middle of the outer side of the central rotating shaft. A connecting nail is slidably connected inside the fixed frame. The lower end of the connecting nail is fixedly connected with a connecting plate. A support bar is fixedly connected to the outer side of the connecting plate. A scraping bar is fixedly connected to the outer side of the support bar. A spring is arranged on the outer side of the connecting nail. A reinforcing rib is fixedly connected to the lower end of the connecting plate. An air inlet pipe is fixedly connected inside the sealed furnace lid. A drainage fan is fixedly connected inside the sealed furnace lid. The drainage fan can suck out the water vapor inside the drying crucible.

[0015] Preferably, a high-temperature resistant motor is fixedly installed at the upper end of the sealed furnace cover, and the output shaft of the high-temperature resistant motor is fixedly connected to the central rotating shaft. The high-temperature resistant motor can drive the central rotating shaft to rotate.

[0016] Preferably, the scraping strip contacts the inner wall of the drying crucible. The scraping strip is made of stainless steel material, and the reinforcing rib is fixedly connected to the supporting strip. The scraping strip can scrape the graphite powder adhered to the outside of the drying crucible.

[0017] Preferably, one end of the spring is fixedly connected to the fixed frame, and the other end of the spring is fixedly connected to the connecting plate. The spring can apply pressure to the connecting plate through elastic force.

[0018] Preferably, a positioning column is fixedly connected to the upper end of the graphite drying furnace. The positioning column is slidably connected to the drying crucible and contacts the sealed furnace cover. The positioning column can position the drying crucible.

[0019] The beneficial effects of the present invention are as follows:

[0020] First, the electrolyte is prepared by mixing sulfuric acid and phosphoric acid. The sulfate ions in sulfuric acid have strong ability to embed into the graphite interlayer and high stripping efficiency, but they are prone to cause excessive oxidation of graphite (generating a large number of oxygen-containing groups, such as -COOH, -OH), and can generate oxygen and sulfur dioxide gases, and at the same time can promote the interlayer stripping. The phosphate ions of phosphoric acid have weak embedding ability, can reduce the fracture of the carbon skeleton, and phosphoric acid has weak acidity, can neutralize the efficiency of the oxidation reaction, and can effectively reduce the excessive oxidation of graphite.

[0021] Second, when drying the prepared solid, the commonly used freeze-drying method is replaced by the high-temperature heating drying method, so that the over-oxidized graphite can be reduced by high-temperature heating, and during the reduction process, the powder can be stirred by the scraping strip and the supporting strip, which can further avoid graphite caking. Description of the Drawings

[0022] For ease of explanation, the present invention is described in detail by the following specific embodiments and drawings.

[0023] Figure 1 It is a schematic diagram of the overall structure of the preparation equipment for the nano-graphite sheet composite material of the present invention;

[0024] Figure 2 For the present invention Figure 1 Enlarged view of the structure of part A.

[0025] In the figure: 1. Graphite drying furnace; 2. Drying crucible; 3. Sealed furnace cover; 4. Constant-temperature electric heating tube; 5. Central rotating shaft; 6. High-temperature resistant motor; 7. Fixed frame; 8. Connecting nail; 9. Connecting plate; 10. Support bar; 11. Scraping bar; 12. Spring; 13. Positioning column; 14. Drainage fan; 15. Air inlet pipe; 16. Reinforcing rib. Specific implementation method

[0026] As Figure 1-2 shown, the following technical solutions are adopted in this specific implementation method:

[0027] Example:

[0028] A preparation method of a nano-graphite sheet composite material includes the following specific steps:

[0029] Step 1: Install the graphite plate at the anode of the electrolytic cell and install the stainless steel sheet at the cathode of the electrolytic cell;

[0030] Step 2: Pour the electrolyte into the interior of the electrolytic cell so that the electrolyte completely submerges the anode and the cathode;

[0031] Step 3: Apply a DC voltage to the anode, bubbles are generated on the surface of the graphite plate at the anode, and at the same time, electrolyte ions are embedded into the interlayer of the graphite, resulting in the expansion of the graphite;

[0032] Step 4: After the graphite layer of the graphite plate expands, it falls off, and the graphite layer disperses into the interior of the electrolyte to form a suspension;

[0033] Step 5: Filter the suspension in Step 4, and then wash the generated solid matter with a cleaning solution;

[0034] Step 6: Put the solid obtained in Step 5 into the interior of the graphite drying furnace 1 for high-temperature drying treatment. Place the washed solid into the interior of the drying crucible 2, then cover the outer side of the graphite drying furnace 1 with the sealed furnace cover 3, cover it tightly and screw the sealed furnace cover 3 tightly. During the process of screwing the sealed furnace cover 3 tightly, the sealed furnace cover 3 squeezes the support bar 10 and the scraping bar 11 against the inner wall of the drying crucible 2 through the central rotating shaft 5. At the same time, the support bar 10 pushes the connecting plate 9 to move upward. During the process of the connecting plate 9 moving upward, the spring 12 can be compressed. After the spring 12 is compressed, it generates an elastic force. The spring 12 can push the scraping bar 11 on the outer side of the support bar 10 below the connecting plate 9 to squeeze against the inner wall of the drying crucible 2 through the generated elastic force. Then start the constant-temperature electric heating tube 4. The heat generated by the constant-temperature electric heating tube 4 can heat the solid inside through the drying crucible 2. At the same time, start the high-temperature resistant motor 6. The high-temperature resistant motor 6 drives the central rotating shaft 5 to rotate. The central rotating shaft 5 drives the connecting nail 8 to rotate around the central rotating shaft 5 through the fixing frame 7. During the rotation of the connecting nail 8, it can drive the support bar 10 and the scraping bar 11 to rotate on the inner wall of the drying crucible 2 through the connecting plate 9, and clean the solid adhered to the inner wall of the drying crucible 2, which can prevent the solid from adhering to the inner wall of the drying crucible 2 and causing overheating. At the same time, the solid inside the drying crucible 2 can be disturbed through the support bar 10, which can make the heating of the solid more uniform. During the heating process, start the drainage fan 14. The drainage fan 14 generates suction, and the suction can suck out the high-temperature water vapor inside the drying crucible 2. After being sucked out, the dry air flow can enter the interior of the drying crucible 2 through the air inlet pipe 15. After heating for 1 - 2 hours, wait for the drying crucible 2 to cool naturally, then take out the drying crucible 2 from the interior of the graphite drying furnace 1 and take out the solid, and nano-graphite flakes can be obtained.

[0035] Among them, the electrolyte in Step 2 is prepared by mixing sulfuric acid and phosphoric acid, and the ratio of sulfuric acid to phosphoric acid is 3:1.

[0036] Among them, the electrolysis time in Step 3 is 40 - 50 minutes.

[0037] A preparation device for a nano-graphite sheet composite material, comprising a graphite drying furnace 1, inside which a drying crucible 2 is slidably connected. The upper end of the graphite drying furnace 1 is threadedly connected with a sealed furnace cover 3. Inside the inner wall of the graphite drying furnace 1, a constant-temperature electric heating tube 4 is fixedly connected. Inside the sealed furnace cover 3, a central rotating shaft 5 is installed through a bearing. In the middle of the outer side of the central rotating shaft 5, a fixing frame 7 is fixedly connected. Inside the fixing frame 7, a connecting nail 8 is slidably connected. The lower end of the connecting nail 8 is fixedly connected with a connecting plate 9. On the outer side of the connecting plate 9, a support bar 10 is fixedly connected. On the outer side of the support bar 10, a scraping bar 11 is fixedly connected. A spring 12 is arranged on the outer side of the connecting nail 8. The lower end of the connecting plate 9 is fixedly connected with a reinforcing rib 16. Inside the sealed furnace cover 3, an air inlet pipe 15 is fixedly connected. Inside the sealed furnace cover 3, a drainage fan 14 is fixedly connected, and the drainage fan 14 can suck out the water vapor inside the drying crucible 2.

[0038] Among them, a high-temperature resistant motor 6 is fixedly installed on the upper end of the sealed furnace cover 3, and the output shaft of the high-temperature resistant motor 6 is fixedly connected with the central rotating shaft 5. The high-temperature resistant motor 6 can drive the central rotating shaft 5 to rotate.

[0039] Among them, the scraping bar 11 contacts the inner wall of the drying crucible 2. The scraping bar 11 is made of stainless steel material. The reinforcing rib 16 is fixedly connected with the support bar 10. The scraping bar 11 can scrape the graphite powder adhered to the outer side of the drying crucible 2.

[0040] Among them, one end of the spring 12 is fixedly connected with the fixing frame 7, and the other end of the spring 12 is fixedly connected with the connecting plate 9. The spring 12 can apply pressure to the connecting plate 9 through its elastic force.

[0041] Among them, a positioning column 13 is fixedly connected to the upper end of the graphite drying furnace 1. The positioning column 13 is slidably connected with the drying crucible 2 and contacts the sealed furnace cover 3. The positioning column 13 can position the drying crucible 2.

[0042] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a nano-graphite sheet composite material, characterized in that: The specific steps are as follows: Step 1: Install the graphite plate at the anode of the electrolytic cell and install the stainless steel sheet at the cathode of the electrolytic cell; Step 2: pour the electrolyte into the electrolytic cell so that the electrolyte completely immerses the anode and cathode; Step 3: Applying a DC voltage to the anode generates bubbles on the surface of the graphite plate at the anode, and at the same time, the electrolyte ions are embedded in the interlayers of the graphite, causing the graphite to expand; Step 4: The graphite layer of the graphite plate expands and falls off, and the graphite layer is dispersed into the electrolyte to form a suspension; Step 5, filtering the suspension in step 4, and then washing the solid matter produced by the filtration with a cleaning solution; Step 6: Place the solid obtained in step 5 into the graphite drying furnace (1) for high-temperature drying treatment, place the washed solid into the drying crucible (2), and then cover the outer side of the graphite drying furnace (1) with a sealed furnace cover (3), cover and tighten the sealed furnace cover (3), and in the process of tightening the sealed furnace cover (3), the sealed furnace cover (3) squeezes the support bar (10) and the scraper bar (11) against the inner wall of the drying crucible (2) through the central rotating shaft (5), and at the same time, the support bar (10) pushes the connecting plate (9) upward. The connecting plate (9) is moved upward, and the spring (12) can be compressed during the upward movement. The spring (12) generates elastic force after being compressed. The spring (12) can push the scraper (11) outside the support bar (10) below the connecting plate (9) to squeeze the inner wall of the drying crucible (2) by generating elastic force, and then start the constant temperature electric heating tube (4). The heat generated by the constant temperature electric heating tube (4) can heat the solid matter inside the drying crucible (2), and at the same time start the high temperature resistant motor (6), and the high temperature resistant motor (6) drives the center to rotate. The central rotating shaft (5) is driven by the fixing frame (7) to drive the connecting pin (8) to rotate around the central rotating shaft (5). During the rotation process, the connecting pin (8) can drive the supporting bar (10) and the scraping bar (11) to rotate on the inner wall of the drying crucible (2) through the connecting plate (9), and clean the solid matter adhered to the inner wall of the drying crucible (2), thereby preventing the solid matter from adhering to the inner wall of the drying crucible (2) and causing overheating. At the same time, the inside of the drying crucible (2) can be cleaned through the supporting bar (10). The fixed object is disturbed to make the heating of the solid object more uniform. During the heating process, the drainage fan (14) is started to generate suction force, which can suck out the high-temperature water vapor in the drying crucible (2). After being sucked out, the dry air flow can enter the drying crucible (2) through the air inlet pipe (15). After heating for 1-2 hours, the drying crucible (2) is waited for to cool naturally, and then the drying crucible (2) is taken out from the graphite drying furnace (1) to take out the solid object, so as to obtain nanographite sheets.

2. The method for preparing a nano-graphite sheet composite material according to claim 1, characterized in that: The electrolyte in step 2 is prepared by mixing sulfuric acid and phosphoric acid, and the ratio of sulfuric acid to phosphoric acid is 3:

1.

3. The method for preparing a nano-graphite sheet composite material according to claim 1, characterized in that: The electrolysis time in step 3 is 40-50 minutes.

4. A preparation device for a nano-graphite sheet composite material, applied to the preparation method for a nano-graphite sheet composite material according to any one of claims 1 to 3, characterized in that: The invention comprises a graphite drying furnace (1), wherein a drying crucible (2) is slidably connected to the inside of the graphite drying furnace (1), a sealed furnace cover (3) is connected to the upper end of the graphite drying furnace (1) via a thread, a constant temperature electric heating pipe (4) is fixedly connected to the inner wall of the graphite drying furnace (1), a central rotating shaft (5) is installed inside the sealed furnace cover (3) via a bearing, a fixing frame (7) is fixedly connected to the middle part of the outer side of the central rotating shaft (5), and a connecting nail (7) is slidably connected to the inside of the fixing frame (7). 8), the lower end of the connecting nail (8) is fixedly connected to a connecting plate (9), the outer side of the connecting plate (9) is fixedly connected to a supporting strip (10), the outer side of the supporting strip (10) is fixedly connected to a scraping strip (11), a spring (12) is arranged on the outer side of the connecting nail (8), the lower end of the connecting plate (9) is fixedly connected to a reinforcing rib (16), the interior of the sealed furnace cover (3) is fixedly connected to an air intake pipe (15), and the interior of the sealed furnace cover (3) is fixedly connected to a drainage fan (14).

5. The preparation device of a nano-graphite sheet composite material according to claim 4, characterized in that: A high temperature resistant motor (6) is fixedly mounted on the upper end of the sealed furnace cover (3), and an output shaft of the high temperature resistant motor (6) is fixedly connected to the central rotating shaft (5).

6. The preparation device of a nano-graphite sheet composite material according to claim 4, characterized in that: The scraper bar (11) contacts the inner wall of the drying crucible (2), and the scraper bar (11) is made of stainless steel. The reinforcing rib (16) is fixedly connected to the supporting bar (10).

7. The preparation device of a nano-graphite sheet composite material according to claim 4, characterized in that: One end of the spring (12) is fixedly connected to the fixing frame (7), and the other end of the spring (12) is fixedly connected to the connecting plate (9).

8. The preparation device of a nano-graphite sheet composite material according to claim 4, characterized in that: A positioning column (13) is fixedly connected to the upper end of the graphite drying furnace (1), the positioning column (13) is slidably connected to the drying crucible (2), and the positioning column (13) is in contact with the sealing furnace cover (3).

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