A graphite intercalation material preparation system and method

Abstract

The present invention relates to a graphite intercalation material preparation system and method, belonging to the technical field of graphite material preparation. The above-mentioned system includes a mixing kettle, a slurry pump, an electrolytic cell and a gas-liquid separator connected in sequence, wherein: a graphite feeding port and a liquid feeding port are arranged on the top of the mixing kettle, and a slurry pump is connected to the bottom to pump the slurry suspension into the electrolytic cell through a cooler; the electrolytic cell includes an anode plate and a cathode plate arranged oppositely and an anode chamber and a cathode chamber separated by an anion exchange membrane; a tail gas outlet is arranged on the top of the gas-liquid separator, and the bottom is connected to the slurry pump. The present invention uses a slurry pump to force the slurry suspension to circulate, which is convenient for the multi-angle intercalation of the intercalation medium to the graphite flakes, avoiding the problems of intercalation dead angles and uneven intercalation; the circulating suspension can timely discharge the bubbles generated in the reaction process to prevent accumulation in the electrolytic cell and causing large fluctuations in the current density per unit area.

Description

Technical Field

[0001] The invention relates to the technical field of graphite materials, and specifically provides a system and method for preparing a graphite intercalation material. Background Art

[0002] Graphene is a two-dimensional crystal. The common graphite is formed by layers of planar carbon atoms stacked in an orderly honeycomb shape. The interlayer force of graphite is weak and it is easy to peel off from each other. When the graphite sheets are peeled into a single layer or several layers, graphene is obtained.

[0003] The electrochemical method is one of the more mature graphene production methods. The main method that can be mass-produced is the electrochemical oxidation method: using cheap graphite as raw material, under the action of an electric field, an oxidizing exfoliation medium (mainly sulfuric acid, nitric acid, hydrogen peroxide, potassium permanganate, etc.) is used to insert graphite flakes in the liquid phase to form graphite intercalation (the name of the material after graphite is intercalated by a liquid medium). During the intercalation process, some carbon atoms in the graphite structure are oxidized, and at the same time, nitric acid and sulfuric acid molecules are embedded in the gaps between graphite layers. The decomposition of graphite intercalation is completed at a high temperature of 800℃-1200℃. At high temperatures, the gaps between graphite layers rapidly release the decomposed gaseous products, and the lattice expands rapidly under the action of air pressure to obtain graphene powder products. The advantages of this electrochemical oxidation method for preparing graphite intercalation are low cost and high yield, and the disadvantages are low chemical purity and a large number of structural defects in the graphene layer. This is mainly because the product contains chemically connected oxygen atoms, sulfur atoms, etc., which seriously decay and reduce most of the mechanical and electronic properties of the material.

[0004] Another electrochemical method for preparing graphite intercalation is to prepare graphene by anodic and cathodic oxidation exfoliation, that is, using a graphite rod as an anode or cathode, and when the power source is working, the ions in the electrolyte move toward the anode or cathode, and the anions and cations enter the anode or cathode graphite rod respectively, causing the graphite to be intercalated and expand in volume. When the volume of the graphite electrode increases to a certain extent, it will eventually fall off from the graphite rod block due to the reduction of the interlayer van der Waals force, forming a layered graphite intercalation with certain oxygen-containing functional groups. This method can produce graphite intercalation with good performance for the production of graphene, but the working area of ​​the electrolysis process is too small, which is not conducive to mass production.

[0005] At the same time, in the prior art, during the electrochemical preparation of graphite intercalants, the shape of the electrolytic cell or the inability to promptly remove the gas generated during the electrolysis process can easily lead to an uneven electric field in the electrolytic cell, which can adversely affect the electrolysis process and product quality. Summary of the invention

[0006] In order to solve the problems existing in the prior art, the present invention provides a graphite intercalation material preparation system and method; in the graphite intercalation material preparation system of the present invention, the circulating slurry suspension can timely discharge the bubbles generated in the reaction process to prevent the bubbles from accumulating in the electrolytic cell and causing a large fluctuation in the current density per unit area; at the same time, the intercalation process of the intercalation medium on the graphite is completed by using cheap graphite flakes and a liquid medium without strong oxidizing effect, so as to prepare the graphite intercalation materials for producing high-quality graphene in batches.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] In one aspect, the present invention provides a graphite intercalation preparation system, comprising a mixing kettle, a slurry pump, an electrolytic cell and a gas-liquid separator connected in sequence, wherein:

[0009] The top of the mixing kettle is provided with a graphite feeding port and a liquid feeding port, and the materials are mixed evenly in the mixing kettle. The bottom of the mixing kettle is connected to the slurry pump, which is used to pump the slurry suspension into the electrolytic cell through the cooler;

[0010] The electrolytic cell comprises an anode plate and a cathode plate arranged opposite to each other and an anode chamber and a cathode chamber separated by an anion exchange membrane;

[0011] The top of the gas-liquid separator is provided with an exhaust gas outlet, and the bottom is connected to the slurry pump, so that the suspension circulates among the slurry pump, the cooler, the electrolytic cell and the gas-liquid separator.

[0012] Furthermore, the anode chamber is the space formed between the anode plate and the anion exchange membrane, and the cathode chamber is the space formed between the cathode plate and the anion exchange membrane; a slurry suspension is arranged in the anode chamber, and a perchloric acid solution with a concentration of 30-50% is arranged in the cathode chamber;

[0013] The feed inlet of the electrolytic cell is located at the lower part of the anode chamber, the discharge port of the electrolytic cell is located at the upper part of the anode chamber, and the gas outlet is located at the top of the cathode chamber.

[0014] Furthermore, an anode hanging ear is provided on the top of the anode plate for connecting to the positive electrode of the power supply; and a cathode hanging ear is provided on the top of the cathode plate for connecting to the negative electrode of the power supply.

[0015] Furthermore, a reaction liquid slurry pump is connected to the bottom of the gas-liquid separator to pump the slurry after the reaction is completed to a subsequent processing system.

[0016] Furthermore, the subsequent processing system includes a filtering device, a washing device, a filter press and an air flow dryer which are arranged in sequence.

[0017] On the other hand, the present invention also provides a method for preparing graphite intercalation material using the above system, comprising:

[0018] Step 1: Add a low concentration perchloric acid solution and graphite flakes into a mixing kettle successively, stir evenly, and obtain a slurry suspension;

[0019] Step 2: The slurry pump pumps the suspension into the anode chamber of the electrolytic cell and cools it through a cooler to keep the suspension temperature below 50°C;

[0020] Step 3: Connect the anode and cathode of the electrolytic cell to the positive and negative electrodes of a DC power supply respectively, and form an electric field between the two plates after power is applied;

[0021] Step 4: electrolyzing the suspension, separating the gas and liquid in the electrolyzed suspension through a gas-liquid separator, sending the liquid to a slurry pump, and then passing through a cooler and entering the anode chamber of the electrolytic cell again for electrolysis;

[0022] Step 5: Repeat step 4 until the suspension is electrolyzed for 3-6 hours and the reaction process is completed;

[0023] Step 6: The residual suspension remaining in the gas-liquid separator is filtered to recover the residual acid, washed with desalted water, filtered by a filter press, and then air-dried. The moisture content of the dried graphite intercalation material is controlled to <1%.

[0024] In the presence of the reaction solution, the anode chamber is enriched with perchlorate ions, and the charge is inserted into the graphite interlayer through the contact surface between the reaction solution and the graphite, until a large amount of ClO4 is generated between the layers. - and HClO4 to form graphite intercalation, an intermediate product for preparing graphene. Some of the oxygen and carbon dioxide produced around the anode rise to the top of the anode chamber in the form of bubbles.

[0025] The gas accumulation and discharge process will cause part of the graphite powder to be separated from the liquid phase, making it unable to effectively complete the electrolysis and intercalation process. Therefore, a slurry pump is used to force the material in the anode chamber to circulate: the circulating suspension is pumped into the lower part of the anode chamber, and the bubbles generated in the chamber are discharged from the anode chamber together with the circulating liquid. The bubbles are removed by the gas separator, and the degassed suspension can be adjusted for acidity, and then pumped into the lower part of the anode chamber by the pump. The suspension is cooled by the cooler and then enters the electrolytic cell to form a material cycle, and the temperature is kept below 50°C.

[0026] At low temperatures, the oxidizing property of perchloric acid <50% is weak and does not react with graphite carbon atoms. The electrochemical and physical properties of the resulting powdered graphene product are significantly superior to those of the acid oxidation method.

[0027] The separated gas is washed and purified with sodium carbonate solution and then discharged. The product sodium hypochlorite after washing can be recycled as industrial salt.

[0028] The hydrogen produced by the cathode during the electrolysis process is discharged through the gas outlet and sent to the gas furnace for combustion, or collected through the gas collecting pipe and sent to the washing tower for washing with alkaline solution. The hydrogen is pressurized by a compressor and can be sold as a product.

[0029] Preferably, in step 1, the solid-liquid volume ratio of graphite flakes to perchloric acid solution is 1:3-1:10.

[0030] Preferably, the concentration of the perchloric acid solution is less than 50%; and the particle size of the graphite flakes is 80-100 meshes.

[0031] Furthermore, in step 4, the voltage during the electrolysis process is 2-10V and the current density is 30-120mA / cm 2 .

[0032] In another aspect, the present invention further provides a method for preparing graphene, wherein the graphite intercalation material prepared by the above method is treated with a hot air flow at a temperature of 300-700° C. to obtain graphene.

[0033] When graphene is produced using the graphite intercalation powder, the powder material is fed into the graphene generator through a feeder. Under the action of a hot air flow at a temperature of 300-700°C, the intercalated perchloric acid produces a large amount of gas, and the equation is shown below.

[0034] 4HClO4=2H2O+7O2+2Cl2

[0035] As the gas is released and diffuses rapidly, the volume of the intercalated material between the graphite layers increases by thousands of times, overcoming the van der Waals force between the graphite layers, and directly exfoliating the graphite sheets in a non-oxidative manner. The graphene layers are opened and the interlayer distance is pulled apart, resulting in a graphene product with a surface area more than 300 times larger than that of graphite flakes, and several or single layers. The chemical bonds between the carbon atoms in the product are not destroyed, and the graphene structure is basically intact, which can give it excellent electrochemical and physical properties. In this way, the product can be used in electronic fields such as supercapacitors and high-energy batteries, where oxidation-based graphene has obvious deficiencies.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) The insertion and stripping of perchlorate ions can reduce the damage to the graphene structure. The graphite intercalation obtained by the operation of the above device has a higher graphene product quality after completing the expansion reaction at 650°C: the conductivity of graphene reaches 1×10 5 s / m or more, with a specific surface area of ​​500m 2 / g or above, graphene is distributed in 5-9 layers and the tablet diameter is 40 microns.

[0038] (2) The solution in the electrolytic cell circulates continuously, and the graphite flakes are not fixed in a certain state, which facilitates the multi-angle intercalation of the graphite flakes by the intercalation medium, avoiding the problems of intercalation dead angles and uneven intercalation.

[0039] (3) The circulating liquid temperature is controlled at <50°C, which allows the suspended material, precipitated material and liquid to form a uniform and stable suspension with a certain viscosity. The ion flow resistance in the acid solution in the suspension increases, forcing the intercalated ions to move between the solid phase graphite layers, which is beneficial to improving the intercalation effect.

[0040] (4) The circulating suspension can promptly discharge the bubbles generated during the reaction process, preventing their accumulation in the electrolytic cell and causing large fluctuations in the current density per unit area.

[0041] (5) The raw materials are cheap and the scale is suitable for expansion, which can realize mass production of graphite intercalation materials.

[0042] (6) Compared with the electrochemical oxidation method, the method of the present invention does not require the addition of strong oxidants during the preparation of the intercalation material, and the intercalation medium rarely reacts chemically with graphite. Compared with other electrochemical methods, the intercalation process of the intercalation medium is completed at a relatively stable and low temperature. Compared with the preparation of graphite intercalation materials by electrolytic cathode or anode rods, the contact area between the solid and liquid phases is large, and the working surface of the intercalation reaction is large. Compared with general electrochemical processes, the working medium is a slurry composed of four phases: gas, liquid, solid suspension, and solid precipitation. It is difficult to control uniform current density and equal reaction opportunities of the slurry in the electrolytic cell. The expansion of the intercalation material is allowed to be completed at a temperature of <700°C. The reaction conditions are relatively mild, which can avoid the high-temperature oxidation reaction affecting the quality and output of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic diagram of the structure of a graphite intercalation material preparation system according to Example 1 of the present invention. DETAILED DESCRIPTION

[0044] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0045] In the present invention, the materials and reagents used can be obtained from commercial sources unless otherwise specified.

[0046] The present invention provides a system and method for preparing graphite intercalation materials, and specific embodiments are as follows.

[0047] Example 1

[0048] A graphite intercalation material preparation system, see Figure 1 , comprising a mixing kettle 3, a slurry pump 4, an electrolytic cell 6 and a gas-liquid separator 15 which are connected in sequence, wherein:

[0049] The top of the mixing kettle 3 is provided with a graphite feed port 1 and a liquid feed port 2, and the materials are mixed evenly in the mixing kettle 3. The bottom of the mixing kettle 3 is connected to a slurry pump 4 for pumping the slurry suspension into the electrolytic cell 6 through a cooler 5;

[0050] The electrolytic cell 6 comprises an anode plate 7 and a cathode plate 8 arranged opposite to each other and an anode chamber and a cathode chamber separated by an anion exchange membrane;

[0051] The top of the gas-liquid separator 15 is provided with an exhaust gas outlet 16 , and the bottom is connected to the slurry pump 4 , so that the suspension circulates among the slurry pump 4 , the cooler 5 , the electrolytic cell 6 and the gas-liquid separator 15 .

[0052] The present invention uses a slurry pump to force the circulation of the slurry suspension, so that the graphite flakes are not fixed in a certain state, which facilitates the multi-angle intercalation of the graphite flakes by the intercalation medium and avoids the occurrence of intercalation dead angles and uneven intercalation; the circulating suspension can timely discharge the bubbles generated in the reaction process to prevent the accumulation in the electrolytic cell and cause a large fluctuation in the current density per unit area.

[0053] Furthermore, the anode chamber is the space formed between the anode plate 7 and the anion exchange membrane, and the cathode chamber is the space formed between the cathode plate 8 and the anion exchange membrane; a slurry suspension is set in the anode chamber, which is a slurry studio, and a perchloric acid solution with a concentration of 30-50% can be set in the cathode chamber; the feed port 10 of the electrolytic cell 6 is located at the lower part of the anode chamber; the discharge port 11 of the electrolytic cell 6 is located at the upper part of the anode chamber, and the gas outlet 14 is located at the top of the cathode chamber, which is convenient for direct discharge of gas during the electrolysis process to prevent problems such as explosion of the electrolytic cell due to gas accumulation. Before the electrolytic cell is put into operation, the cathode chamber is filled with acid through the gas outlet 14, and the hydrogen generated in the cathode chamber is discharged during formal operation.

[0054] Furthermore, an anode hanging ear 12 may be provided on the top of the anode plate 7 for connecting to the positive electrode of the power supply; and a cathode hanging ear 13 may be provided on the top of the cathode plate 8 for connecting to the negative electrode of the power supply.

[0055] Furthermore, a reaction liquid slurry pump 17 may be connected to the bottom of the gas-liquid separator 15 , and the reaction liquid slurry pump 17 is used to pump the slurry after the reaction is completed to a subsequent processing system 18 .

[0056] Furthermore, the subsequent processing system 18 may include a filtering device, a washing device, a filter press and an air flow dryer which are arranged in sequence to purify and dry the graphite intercalation material.

[0057] Preferably, after the electrolysis reaction is completed, the acid liquid recovered by the filtering device can be used to replace the slurry after the reaction in the electrolytic cell and transfer it to the gas-liquid separator.

[0058] The circulating liquid is controlled to a temperature of <50°C by the cooler, so that the suspended material, precipitated material and liquid form a uniform and stable suspension with a certain viscosity. The ion flow resistance in the acid solution in the suspension increases, forcing the intercalated ions to move between the solid phase graphite layers, which is beneficial to improving the intercalation effect. Valves are set between the above devices for easy operation.

[0059] Example 2

[0060] A method for preparing a graphite intercalation material using the system of Example 1 comprises:

[0061] Step 1: Add 40% perchloric acid solution and 80-120 mesh powdered graphite flakes into a mixing kettle successively, and control the solid-liquid (volume) ratio to 1:8. Stir the powdered graphite flakes into the perchloric acid solution and stir evenly to obtain a suspension;

[0062] Step 2: The slurry pump pumps the suspension into the anode chamber of the electrolytic cell and cools it through a cooler to keep the suspension temperature below 30°C;

[0063] Step 3: Connect the anode and cathode of the electrolytic cell to the positive and negative electrodes of a DC power supply respectively, and form an electric field between the two plates after power is applied;

[0064] Step 4: The suspension is electrolyzed at a voltage of 10 V and a current density of 90 mA / cm 2 The electrolyzed suspension is separated into gas and liquid by a gas-liquid separator, and the liquid is sent to a slurry pump, and then enters the anode chamber of the electrolytic cell again after passing through a cooler for electrolysis; the slurry pump is used to establish a circulation of the suspension between the electrolytic cell, the gas-liquid separator and the cooler;

[0065] Step 5: Repeat step 4 until the suspension is electrolyzed for 5 hours and the reaction process is completed;

[0066] Step 6: The residual suspension remaining in the gas-liquid separator is filtered to recover the residual acid, washed with desalted water, filtered by a filter press, and then air-dried. The moisture content of the dried graphite intercalation material is controlled to <1%.

[0067] Example 3

[0068] A method for preparing a graphite intercalation material using the system of Example 1 comprises:

[0069] Step 1: Add 30% perchloric acid solution and 80-120 mesh powdered graphite flakes into a mixing kettle successively, and control the solid-liquid (volume) ratio to 1:3. Stir the powdered graphite flakes into the perchloric acid solution and stir evenly to obtain a suspension;

[0070] Step 2: The slurry pump pumps the suspension into the anode chamber of the electrolytic cell and cools it through a cooler to keep the suspension temperature below 50°C;

[0071] Step 3: Connect the anode and cathode of the electrolytic cell to the positive and negative electrodes of a DC power supply respectively, and form an electric field between the two plates after power is applied;

[0072] Step 4: The suspension is electrolyzed at a voltage of 2 V and a current density of 120 mA / cm 2 The electrolyzed suspension is separated into gas and liquid by a gas-liquid separator, and the liquid is sent to a slurry pump, and then enters the anode chamber of the electrolytic cell again after passing through a cooler for electrolysis; the slurry pump is used to establish a circulation of the suspension between the electrolytic cell, the gas-liquid separator and the cooler;

[0073] Step 5: Repeat step 4 until the suspension is electrolyzed for 6 hours and the reaction process is completed;

[0074] Step 6: The residual suspension remaining in the gas-liquid separator is filtered to recover the residual acid, washed with desalted water, filtered by a filter press, and then air-dried. The moisture content of the dried graphite intercalation material is controlled to <1%.

[0075] During this period, the bubbles generated in the anode chamber are discharged from the anode chamber together with the circulating liquid. The bubbles are removed by the gas separator, and the acidity of the solution is adjusted before being pumped into the lower part of the anode chamber to form a material cycle. A small amount of high-concentration acid is added during the process to maintain the acid concentration in the electrolytic cell unchanged. The separated gas is washed and purified with alkaline solution and then discharged.

[0076] The hydrogen and other gases produced by the cathode during the electrolysis process are collected through a gas collecting pipe and sent to a washing tower for washing with alkaline solution. The hydrogen is then pressurized by a compressor and sold as a product.

[0077] Example 4

[0078] A method for preparing a graphite intercalation material using the system of Example 1 comprises:

[0079] Step 1: Add a 40% concentration of perchloric acid solution and 80-120 mesh powdered graphite flakes into a mixing kettle successively, and control the solid-liquid (volume) ratio to be 1:10. Stir the powdered graphite flakes into the perchloric acid solution and stir evenly to obtain a suspension;

[0080] Step 2: The slurry pump pumps the suspension into the anode chamber of the electrolytic cell and cools it through a cooler to keep the suspension temperature below 30°C;

[0081] Step 3: Connect the anode and cathode of the electrolytic cell to the positive and negative electrodes of a DC power supply respectively, and form an electric field between the two plates after power is applied;

[0082] Step 4: The suspension is electrolyzed at a voltage of 10 V and a current density of 30 mA / cm 2 The electrolyzed suspension is separated into gas and liquid by a gas-liquid separator, and the liquid is sent to a slurry pump, and then enters the anode chamber of the electrolytic cell again after passing through a cooler for electrolysis; the slurry pump is used to establish a circulation of the suspension between the electrolytic cell, the gas-liquid separator and the cooler;

[0083] Step 5: Repeat step 4 until the suspension is electrolyzed for 3 hours and the reaction process is completed;

[0084] Step 6: The residual suspension remaining in the gas-liquid separator is filtered to recover the residual acid, washed with desalted water, filtered by a filter press, and then air-dried. The moisture content of the dried graphite intercalation material is controlled to <1%.

[0085] To further illustrate the beneficial effects of the present invention, due to limited space, only Example 2 is taken as an example to construct a comparative example as follows.

[0086] Comparative Example 1

[0087] A method for preparing a graphite intercalation material comprises:

[0088] Steps 1-3 are the same as in Example 2;

[0089] Step 4: The suspension is electrolyzed at a voltage of 10 V and a current density of 90 mA / cm 2 , the electrolysis time is 5 hours, and the reaction process is completed; this step does not carry out forced circulation of the suspension;

[0090] Step 5: The residual suspension remaining in the gas-liquid separator is filtered to recover the residual acid, washed with desalted water, filtered by a filter press, and then air-dried. The moisture content of the dried graphite intercalation material is controlled to <1%.

[0091] Comparative Example 2

[0092] A method for preparing a graphite intercalation material comprises:

[0093] Step 1 is the same as in Example 2;

[0094] Step 2: The slurry pump pumps the suspension into the anode chamber of the electrolyzer without cooling it through a cooler;

[0095] Step 3 is the same as in Example 2;

[0096] Step 4: The suspension is electrolyzed at a voltage of 10 V and a current density of 90 mA / cm 2 The electrolyzed suspension is separated into gas and liquid by a gas-liquid separator, and the liquid is sent to a slurry pump and enters the anode chamber of the electrolytic cell again for electrolysis; the slurry pump is used to establish a circulation of the suspension between the electrolytic cell and the gas-liquid separator;

[0097] Steps 5-6 are the same as in Example 2.

[0098] Comparative Example 3

[0099] The 40% perchloric acid solution in step 1 was replaced with a 60% perchloric acid solution, and the other conditions were the same as those in Example 2.

[0100] Comparative Example 4

[0101] The 40% perchloric acid solution in step 1 is replaced with a 60% perchloric acid solution, and no cooling is performed in the cooler in step 2; the remaining conditions are the same as those in Example 2.

[0102] The graphite intercalation products prepared in the above-mentioned Examples 2-4 and Comparative Examples 1-4 were subjected to hot air flow expansion reaction at 650° C. to obtain graphene. The performance of the obtained graphene was tested, and the results are shown in Table 1.

[0103] Table 1

[0104]

[0105] As can be seen from the above table, the graphene structure prepared by the system and method of the present invention is complete, with high conductivity and large specific surface area. When the system is not circulated (Comparative Example 1), due to the generation of bubbles during electrolysis, the graphite intercalation efficiency is low, the obtained graphene is thicker, and the performance in all aspects is poor; when the system is not cooled (Comparative Example 2), due to the heat generated during the electrolysis process, the suspension temperature is increased, the oxidizing ability of the electrolyte is enhanced, so that the carbon content in the prepared graphene is reduced, and the prepared graphene structure is incomplete. The above problems will also occur when the concentration of perchloric acid solution is increased (Comparative Example 3) and not cooled (Comparative Example 4) at the same time, the perchloric acid concentration is too high and the oxidizability is enhanced, and the temperature is not circulated at the same time to increase the temperature, and the prepared graphene is subjected to strong oxidation, so that the carbon content in the prepared graphene is reduced, and the oxygen content is increased, which has an impact on the application of graphene.

[0106] In summary, the slurry suspension circulating in the graphite intercalation material preparation system of the present invention can timely discharge the bubbles generated in the reaction process to prevent the bubbles from accumulating in the electrolytic cell and causing large fluctuations in the current density per unit area; at the same time, the intercalation process of the intercalation medium on the graphite is completed by using cheap graphite flakes and a liquid medium without strong oxidizing effect, so as to prepare graphite intercalation materials for the production of high-quality graphene in batches.

[0107] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A graphite intercalation material preparation system, characterized in that: It includes a mixing kettle, a slurry pump, an electrolytic cell and a gas-liquid separator which are connected in sequence, wherein: The top of the mixing kettle is provided with a graphite feeding port and a liquid feeding port, and the materials are mixed evenly in the mixing kettle. The bottom of the mixing kettle is connected to the slurry pump, which is used to pump the slurry suspension into the electrolytic cell through the cooler; The electrolytic cell comprises an anode plate and a cathode plate arranged opposite to each other and an anode chamber and a cathode chamber separated by an anion exchange membrane; The top of the gas-liquid separator is provided with an exhaust gas outlet, and the bottom is connected to the slurry pump, so that the suspension circulates among the slurry pump, the cooler, the electrolytic cell and the gas-liquid separator.

2. The graphite intercalation material preparation system according to claim 1, characterized in that: The anode chamber is the space between the anode plate and the anion exchange membrane, and the cathode chamber is the space between the cathode plate and the anion exchange membrane; a slurry suspension is arranged in the anode chamber, and a perchloric acid solution with a concentration of 30-50% is arranged in the cathode chamber; The feed inlet of the electrolytic cell is located at the lower part of the anode chamber, the discharge port of the electrolytic cell is located at the upper part of the anode chamber, and the top of the cathode chamber is provided with a gas outlet.

3. The graphite intercalation material preparation system according to claim 1, characterized in that: The top of the anode plate is provided with an anode hanging ear for connecting the positive pole of the power supply; the top of the cathode plate is provided with a cathode hanging ear for connecting the negative pole of the power supply.

4. The graphite intercalation preparation system according to claim 1, characterized in that: The bottom of the gas-liquid separator is also connected to a reaction liquid slurry pump for pumping the suspension after the reaction is completed to a subsequent processing system.

5. The graphite intercalation material preparation system according to claim 4, characterized in that: The subsequent processing system comprises a filtering device, a washing device, a filter press and an air flow dryer which are arranged in sequence.

6. A method for preparing graphite intercalation using the system according to any one of claims 1 to 5, characterized in that: include: Step 1: Add a low concentration perchloric acid solution and graphite flakes into a mixing kettle successively, stir evenly, and obtain a slurry suspension; Step 2: The slurry pump pumps the suspension into the anode chamber of the electrolytic cell and cools it through a cooler to keep the suspension temperature below 50°C; Step 3: Connect the anode and cathode of the electrolytic cell to the positive and negative electrodes of a DC power supply respectively, and form an electric field between the two plates after power is applied; Step 4: electrolyze and intercalate the suspension, separate the gas and liquid in the electrolyzed suspension through a gas-liquid separator, and send the liquid to a slurry pump, and then enter the anode chamber of the electrolytic cell again after passing through a cooler for electrolysis; Step 5: Repeat step 4 until the suspension is electrolyzed for 3-6 hours and the reaction process is completed; Step 6: The liquid remaining in the gas-liquid separator is filtered to recover the residual acid, then washed with desalted water, filtered by a filter press, and then air-dried. The moisture content of the dried graphite intercalation material is controlled to <1%.

7. The method according to claim 6, characterized in that In the step 1, the solid-liquid volume ratio of graphite flakes to perchloric acid solution is 1:3-1:

10.

8. The method according to claim 7, characterized in that The concentration of the perchloric acid solution is less than 50%; the particle size of the graphite flakes is 80-100 meshes.

9. The method according to claim 6, characterized in that In step 4, the voltage during the electrolysis process is 2-10V and the current density is 30-120mA / cm 2 .

10. A method for preparing graphene, characterized in that: Graphene can be obtained by treating the graphite intercalation material prepared by the method described in any one of claims 6 to 9 with a hot air flow at a temperature of 300-700°C.

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