1. A high porosity carbon black characterized by a porosity of 1.2 to 3.0.

2. A preparation method of high-porosity carbon black is characterized by comprising the following steps:

(1) under the protection of inert gas, raising the temperature of the carbon black to 1000-1500 ℃;

(2) and (3) introducing an oxidant, controlling the gas flow rate of the oxidant, and reacting for a period of time at 1000-1500 ℃ to obtain the high-porosity carbon black.

3. The method of claim 2, wherein the inert gas is one or more of nitrogen, helium, and argon.

4. The method of claim 2, wherein the oxidizing agent is a gas comprising one or more of oxygen, ozone, water vapor, nitric oxide, nitrogen dioxide, sulfur trioxide, and carbon dioxide.

5. The method according to claim 2, wherein the gas flow rate of the oxidizing agent is 2L/min to 20L/min.

6. The method of claim 2, wherein the reaction time is from 0.5h to 15 h.

7. A preparation device of high-porosity carbon black comprises a reaction device, an electric heating device, a transmission device, a riding wheel catch wheel device, a sealing device and an end cover, and is characterized in that the reaction device comprises a reaction kettle barrel; the reaction kettle barrel comprises a reaction kettle inner barrel and a reaction kettle outer barrel; a water jacket is arranged between the inner barrel body and the outer barrel body of the reaction kettle; a water inlet and a water outlet are formed in the outer barrel of the reaction kettle, and diversion trenches are respectively formed in the water outlet; a plurality of shoveling plates are arranged on the inner wall of the cylinder body in the reaction kettle; the electric heating device is a heating rod; the transmission device comprises a driving gear and a gear ring; the gear ring is positioned on the wall of the outer cylinder of the reaction kettle; the bottom of the front end and the bottom of the rear end of the outer cylinder of the reaction kettle are respectively provided with a riding wheel retaining wheel device; the outer cylinder body of the reaction kettle is provided with a rolling ring; the sealing device comprises a compression spring and a sealing ring; the end cover and the reaction kettle are fastened through a positioning bolt; the inner side of the end cover is made of high-temperature-resistant heat-insulating castable; end cover sliding supports are arranged on two sides of the outer wall of the end cover; and the outer wall of the end cover is provided with an air inlet, an air outlet and a vacuum pipeline port.

8. The manufacturing apparatus of claim 7, wherein the shoveling plates are distributed in parallel on the inner wall of the reaction vessel cylinder.

9. The manufacturing apparatus according to claim 7, wherein the heating rod is a groove-shaped heating rod; the heating rod is a silicon-carbon rod or a silicon-molybdenum rod.

10. The application of high-porosity carbon black in the fields of rubber, resin materials, coatings, energy storage materials, batteries and the like.

Disclosure of Invention

The invention discloses a high porosity carbon black, the porosity of which is 1.2-3.0; preferably 1.4 to 3.0; more preferably 1.6-3.0; most preferably 1.8-2.8.

The invention also discloses a preparation method of the high-porosity carbon black, which comprises the following steps:

(1) under the protection of inert gas, raising the temperature of the carbon black to 1000-1500 ℃;

(2) and (3) introducing an oxidant, controlling the gas flow rate of the oxidant, and reacting for a period of time at 1000-1500 ℃ to prepare the carbon black with high porosity.

The porosity referred to in the present invention means carbon black porosity, which is one of the surface characteristics of carbon black, and is used to characterize the degree of micropores on the surface of carbon black particles, which is the ratio of the total specific surface area to the external specific surface area of carbon black. The BET nitrogen surface area generally reflects the total specific surface area of the carbon black (i.e., including the external surface area and the surface area attributable to mesopores and micropores), while the STSA surface area generally reflects only the external surface area of the carbon black and the surface area attributable to mesopores (i.e., excluding the surface area attributable to micropores). The present invention uses the ratio of BET to STSA, BET/STSA, to characterize porosity. The present invention determines BET and STSA according to the national standard GB/T10722-2014. If the ratio of the total specific surface area to the external specific surface area of the carbon black particles is equal to 1, the carbon black has no porosity, if this ratio is clearly higher than 1, which indicates that these carbon blacks have a high porosity. The larger the ratio, the rougher and porous the surface of the carbon black, and the higher the porosity.

As used herein, carbon black used to prepare high porosity carbon black refers to carbon black obtained by any method, including but not limited to contact, furnace and fumed carbon blacks.

The carbon black obtained by the process of the invention has a density of from 1S/cm to 12S/cm; preferably 2S/cm to 10S/cm; more preferably 3S/cm to 8S/cm; most preferably 4S/cm to 7S/cm.

The inert gas used in the present invention may preferably be one or more of nitrogen, helium and argon. The inert gas is introduced into the reaction kettle in order to remove air in the reaction kettle, and the carbon black is heated to the specified reaction temperature under the inert gas environment.

The oxidant referred to in the present invention may be a gas, and may be a gas containing one or more of oxygen, ozone, water vapor, nitric oxide, nitrogen dioxide, sulfur trioxide, and carbon dioxide. Preferably one or more of water vapor, nitric oxide, nitrogen dioxide and carbon dioxide gas, more preferably water vapor or carbon dioxide gas, and most preferably carbon dioxide gas.

The gas flow rate is 2L/min-20L/min; preferably 3L/min-15L/min; more preferably 8L/min-12L/min; the reaction time is 0.5h-15 h; preferably 1h-10 h; more preferably from 2h to 8 h. At this gas flow rate, the reaction time is controlled so that the surface of the carbon black in the system is "etched" to some extent, thereby obtaining carbon black with a specified porosity.

The term "etching" as used herein refers to an oxidation reaction between the oxidizing agent and the surface of the carbon black, wherein the faster the flow rate of the oxidizing agent gas, the longer the reaction time, and the deeper the oxidation reaction between the oxidizing agent and the surface of the carbon black, the higher the porosity of the obtained carbon black.

The in-situ etching of the carbon black refers to the following steps: the molecules of the oxidant react with the active sites on the surface of the carbon black in a high-temperature environment, the exposed carbon atoms are continuously attacked after the carbon atoms on the surface are removed, and the carbon black with certain porosity can be obtained by controlling the reaction time and the flow rate of the oxidant in the reaction kettle.

The pore volume referred to herein is the total pore volume per unit mass of carbon black.

The porosity is defined as the percentage of the pore volume in this size range to the total pore volume of the carbon black, and represents the amount of material pores.

The invention also discloses a preparation device of the high-porosity carbon black, which comprises a reaction device, an electric heating device, a transmission device, a riding wheel catch wheel device, a sealing device and an end cover; the reaction device comprises a reaction kettle barrel; the reaction kettle barrel comprises a reaction kettle inner barrel and a reaction kettle outer barrel; a water jacket is arranged between the inner barrel body and the outer barrel body of the reaction kettle; a water inlet and a water outlet are formed in the outer barrel of the reaction kettle, and diversion trenches are respectively formed in the water outlet; a plurality of shoveling plates are arranged on the inner wall of the cylinder body in the reaction kettle; the electric heating device is a heating rod; the transmission device comprises a driving gear and a gear ring; the gear ring is positioned on the wall of the outer cylinder of the reaction kettle; the bottom of the front end and the bottom of the rear end of the outer cylinder of the reaction kettle are respectively provided with a riding wheel retaining wheel device; the outer cylinder body of the reaction kettle is provided with a rolling ring; the sealing device comprises a compression spring and a sealing ring; the end cover and the reaction kettle are fastened through a positioning bolt; the inner side of the end cover is made of high-temperature-resistant heat-insulating castable; end cover sliding supports are arranged on two sides of the outer wall of the end cover; and the outer wall of the end cover is provided with an air inlet, an air outlet and a vacuum pipeline port.

The water jacket is used for cooling the circular flow of water and cooling the inner cylinder of the reaction kettle; the guide groove guides and directionally discharges the cooling water.

The outer barrel of reation kettle is equipped with 1 water inlet and 2 delivery ports.

And the water outlet is respectively provided with 1 diversion trench.

6 to 18 shovelling plates are arranged on the inner wall of the cylinder body in the reaction kettle; the height of the shoveling plates accounts for 1/20-1/10 of the inner diameter of the reaction kettle barrel; the shoveling plates are uniformly distributed on the inner wall of the reaction kettle barrel in parallel; the shoveling plate can ensure that the carbon black is fully and uniformly heated in the reaction process, and the reaction efficiency is improved.

The electric heating device comprises 1 to 6 heating rods; the heating rod is a groove-shaped heating rod; the heating rods are high-temperature-resistant and corrosion-resistant silicon-carbon rods or silicon-molybdenum rods, the heating temperature can reach 1500 ℃, and the heating length and the number of the heating rods can be adjusted according to the size of a cylinder body in the reaction kettle and the required temperature.

The gear ring is positioned on the wall of the outer cylinder of the reaction kettle and drives the whole reaction kettle cylinder to rotate through meshing with the driving gear.

The riding wheel supports the whole device through a rolling ring which is arranged on the outer barrel of the reaction kettle and is supported, the rotation of the reaction kettle in the operation process is ensured, and the blocking wheel prevents the reaction kettle from sliding in the operation process.

The sealing device comprises a compression spring and a sealing ring, when the sealing device is extruded by external force, the sealing ring has certain flexibility due to the expansion of the compression spring, the abrasion of the sealing ring can be reduced, the end cover and the reaction kettle are fastened through a positioning bolt, the sealing mechanism is firmer, the bolt is loosened during feeding, the end cover is opened, and materials are placed in the reaction kettle.

The inner side of the end cover device is made of high-temperature-resistant heat-insulating pouring materials, so that the overtemperature of the end cover is prevented.

And end cover sliding supports are arranged on two sides of the outer wall of the end cover, so that the end cover can horizontally slide along the guide rail at the bottom to open or close the end cover.

The outer wall of the end cover is provided with a pressure gauge and a temperature control system, the pressure gauge is used for monitoring the pressure inside the reaction kettle in real time, and the temperature and the heating time in the kettle can be controlled through the temperature control system.

The vacuum pipeline port is connected with a vacuum pump, and air in the kettle is pumped out before gas is introduced, so that the reaction kettle is in a micro negative pressure state. The micro negative pressure is-0.03 MPa to-0.12 MPa.

The specific implementation process is as follows: putting a certain amount of carbon black into a cylinder in a reaction kettle, closing an end cover, fastening the end cover by using a positioning bolt, opening a vacuum pump, pumping air in the cylinder in the reaction kettle out through a vacuum pipeline port to enable the air to be under-0.03 MPa to-0.12 MPa, opening an air inlet to introduce inert gas, opening an air outlet when the pressure in the cylinder in the reaction kettle reaches about 0MPa, and adjusting the flow rate of the air inlet to enable the pressure in the cylinder in the reaction kettle to be kept stable. Opening a heating device to set the temperature and the heating rate of the reaction kettle, opening a water inlet and a water outlet to cool and protect a barrel in the reaction kettle, starting a transmission device and a riding wheel catch wheel device in the heating process to ensure that the carbon black is fully and uniformly heated, closing the inert gas at the air inlet when the required high temperature is reached under the protection of the inert gas, starting an oxidant gas, adjusting the air inlet flow rate to ensure that the gas is closed after the reaction is carried out for 0.5 to 15 hours under the high-temperature environment, then cooling the barrel of the reaction kettle by adopting cooling water under the protection of the inert gas, completing the 'in-situ' etching of the carbon black, and preparing the carbon black with high porosity.

The invention also discloses application of the high-porosity carbon black in the fields of rubber, resin materials, coatings, energy storage materials, batteries and the like.

Technical effects

1. The preparation method of the high-porosity carbon black disclosed by the invention can carry out etching reaction on the carbon black by using gas as an oxidant, has the advantages of simple production process, environmental protection, stable reaction conditions and high gas utilization rate, and can obtain carbon black particles with low impurity content, large specific surface area and high porosity.

2. The reaction kettle barrel in the process of the invention is protected by the water jacket, so that higher reaction temperature can be reached, the requirement of high temperature on the material of the reaction kettle barrel is overcome, the temperature reaction condition of oxidant gas is met, the special reaction kettle barrel structure can ensure that gas molecules and carbon black fully react, the gas utilization rate is improved, carbon black particles with high specific surface area and uniform porosity can be prepared, and the problem that the traditional carbon black reaction furnace cannot produce carbon black with high porosity is solved.

3. According to the invention, the carbon black is etched by adopting an oxidant, and the surface structure of the carbon black is changed under a high-temperature condition by utilizing a specific gas-phase reaction kettle cylinder, so that the porosity of the surface of the carbon black is increased, the carbon black is crushed into aggregates with smaller particle size, the roughness of the surface of the carbon black and the average contact area among particles are obviously improved, and meanwhile, functional groups on the surface of the carbon black are reduced, so that the conductivity of the carbon black is obviously improved.

4. The microporous structure in the carbon black is mainly caused by the erosion of the oxidant to the carbon black at high temperature, the BET specific surface area of the carbon black is continuously increased along with the extension of the oxidation time, the change of the external specific surface area is small, therefore, the ratio of the BET nitrogen surface area to the STSA is gradually improved, the ratio reaches 1.6-3.0, meanwhile, the specificity of the barrel structure of the reaction kettle is adopted, the stability of the internal temperature can be ensured under the condition that the heat in the barrel reaches the oxidation temperature, the full reaction of gas molecules and the carbon black can be ensured, the gas utilization rate is improved, the excessive erosion of the carbon black can be avoided by adjusting the process conditions of the gas flow rate and the reaction time, so that the carbon black particles with high specific surface area and uniform porosity are prepared, and the problem that the carbon black with high porosity cannot be produced by the traditional carbon black reaction furnace is solved.

Drawings

FIG. 1 is a schematic view of the structure of a production apparatus of the present invention.

Fig. 2 is a partial schematic view of the end cap.

1. A reaction kettle inner cylinder body; 2. an outer cylinder of the reaction kettle; 3. an electric heating device; 4. an end cap; 4.1 end cover sliding support; 5. a transmission device; 6. a riding wheel catch wheel device; 7. rolling a ring; 8. a ring gear; 9. a water inlet; 10. a water outlet; 11. a sealing device; 12. shoveling plates; 13. an air inlet; 14. an air outlet; 15. a temperature control system; 16. a pressure gauge; 17. a vacuum line port.

FIG. 3 shows the particle size distribution of carbon black N134, N134 treated in example 1, and N134 treated in example 2, measured by a disk centrifugal settler.

Fig. 4 is a graph of specific charge-discharge capacity at 0.2C for batteries assembled with different carbon blacks.

FIG. 5 is a graph of current density versus specific capacitance for different carbon black samples.

Examples

The following examples are further illustrative of the present invention and are not intended to be limiting thereof.

Example 1

100g of carbon black is put into a barrel in a reaction kettle, an end cover is closed and fastened by a positioning bolt, a vacuum pump is started to pump out air in the barrel in the reaction kettle through a vacuum pipeline port, the reaction kettle is vacuumized to-0.05 MPa, an air inlet is opened to introduce nitrogen, when the pressure in the barrel in the reaction kettle reaches about 0MPa, an air outlet is opened, the flow velocity of the air inlet is adjusted, and the pressure in the barrel in the reaction kettle is kept stable. Opening a heating device to set the temperature of the reaction kettle to be 1000 ℃ and the heating rate to be 10 ℃/min, simultaneously opening a water inlet and a water outlet to cool and protect a cylinder in the reaction kettle, starting a transmission device and a riding wheel catch wheel device in the heating process to ensure that the carbon black is fully and uniformly heated, closing nitrogen at the air inlet when the temperature reaches 1000 ℃ under the protection of nitrogen gas, starting steam gas, adjusting the air inlet flow rate to be 2L/min, closing the steam after reacting for 3h, finally cooling the cylinder of the reaction kettle by adopting cooling water under the protection of the nitrogen gas, completing the 'in-situ' etching of the carbon black, and preparing the carbon black with high porosity.

Example 2

200g of carbon black is put into a barrel in a reaction kettle, an end cover is closed and fastened by a positioning bolt, a vacuum pump is started to pump out air in the barrel in the reaction kettle through a vacuum pipeline port, the reaction kettle is vacuumized to-0.08 MPa, an air inlet is opened to introduce argon, when the pressure in the barrel in the reaction kettle reaches about 0MPa, an air outlet is opened, the flow velocity of the air inlet is adjusted, and the pressure in the barrel in the reaction kettle is kept stable. Opening a heating device to set the temperature of the reaction kettle to be 1500 ℃ and the heating rate to be 5 ℃/min, simultaneously opening a water inlet and a water outlet to cool and protect a barrel in the reaction kettle, starting a transmission device and a riding wheel catch wheel device in the heating process to ensure that the carbon black is fully and uniformly heated, closing argon at the air inlet when the temperature reaches 1500 ℃ under the protection of argon gas, starting carbon dioxide gas, adjusting the air inlet flow rate to be 10L/min, closing the gas after reacting for 1h, finally cooling the barrel of the reaction kettle by using cooling water under the protection of the argon gas, completing the 'in-situ' etching of the carbon black, and preparing the carbon black with high porosity.

The particle size distribution was analyzed by a disc centrifugal settler test, and it can be seen from the test curve that the particle size distribution of the treated carbon black is significantly smaller than that of the untreated carbon black (taking N134 as an example), see FIG. 3.

BJH N of treated and untreated carbon blacks₂The adsorption pore test results are shown in table 1 (taking N234 as an example).

Instrument model American microphone (Micrometrics) ASAP 2460 specific Surface Area and Aperture Analyzer (The ASAP 2460Surface Area and Porosity Analyzer)

The instrument manufacturer: mimorruike (Shanghai) instruments Ltd

Degassing temperature: 120 ℃; degassing time: 6 h; adsorbing gas: n2

Liquid nitrogen temperature: -195.800 deg.C

TABLE 1

And (4) conclusion: the number of micropores and small mesopores of the carbon black after treatment is increased, so that the pore diameter distribution of the powder is concentrated to the range of 2nm-10nm, and the pore volume is obviously increased.

The resistivity and conductivity test results are shown in table 2.

Pressing carbon black powder into a sheet, and testing by adopting a four-probe resistivity instrument, wherein the resistivity and the conductivity are tested:

the instrument model is as follows: RTS-8 type four-probe tester

The probe head model: FT-201

The manufacturer: guangzhou four-probe technology

TABLE 2

And (4) conclusion: after the carbon black is treated, the resistivity is reduced, and the conductivity is obviously improved.

The results of the porosity tests for the treated and untreated carbon blacks are shown in table 3. The test was performed according to GB/T10722-2014.

TABLE 3

And (4) conclusion: the porosity (i.e., BET/STSA value) of the treated carbon black is significantly increased.

And (3) testing the battery performance:

and (3) assembling the CR2025 button lithium battery by using N134 and high-porosity carbon black as conductive agents of the positive pole piece respectively, and testing the assembled button battery by adopting blue electricity. The procedure of the charge and discharge test is as follows: the battery is charged at a constant current with a certain current until the voltage reaches 3.8V, and then the battery is charged at a constant voltage until the current is less than a certain value, and the charging process is finished; the battery is discharged with constant current until the voltage is 2.7, and the discharging process is finished. Fig. 4 is a graph of charge and discharge performance at 0.2C for cells assembled with different carbon blacks.

It can be seen from fig. 4 that in the same lithium battery, the specific capacity of N134 is 151.0mAh/g, and the specific capacities of the embodiment 1 and the embodiment 2 are 164mAh/g and 172mAh/g, respectively, which shows that the specific discharge capacity (SC) of the modified carbon black as a conductive agent is improved by 13-20mAh/g compared with that of the original carbon black under the same discharge rate.

Table 4 shows the specific capacitance values for different carbon black samples at different current densities.

TABLE 4

And (3) testing the performance of the capacitor:

different samples were prepared as active: carbon black: PTFE-8: 1: 1, preparing a foamed nickel electrode, and assembling a three-electrode by taking 6mol/L KOH solution as electrolyte. And carrying out constant current charge and discharge test on the three electrodes by using an electrochemical workstation. The test voltages are respectively: -1.1 to 0.1V and 2.0 to 4.2V, and performing charge and discharge tests on the material under different multiplying factors. The CV specific capacitance test results are shown in fig. 5, table 4 and table 5.

Table 5 is the capacity retention for different carbon black samples at different current densities.

TABLE 5

From the data in FIG. 5, Table 4 and Table 5, it is seen that the specific capacitance of the supercapacitor is improved by 10-50F/g and the retention is increased by 15-30% by using the highly porous carbon black as a conductive agent under the same current density compared with the common carbon black.