Hollow spherical capacitor carbon based on coal pitch and preparation method and application thereof

Abstract

The invention belongs to the technical field of capacitor carbon preparation, and particularly relates to hollow spherical capacitor carbon based on coal pitch and a preparation method and application thereof. The hollow spherical capacitance carbon is prepared by taking coal pitch as a raw material, and the limitation of a traditional carbon source is broken through; and dispersing agent assistance, thermal annealing, high-temperature carbonization, activating treatment and other processes are adopted, so that the specific surface area, the microporosity and the capacitive performance of the capacitive carbon are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of capacitor carbon preparation, and in particular relates to a hollow spherical capacitor carbon based on coal tar pitch, and a preparation method and application thereof. Background Art

[0002] In recent years, electrochemical energy storage technology has made significant progress in the energy storage field. Supercapacitors offer advantages such as high energy storage, long cycle life, high power density, rapid charge and discharge, and high operating current. Furthermore, NVIDIA's GPU industry standards have placed higher requirements on capacitors, and the supercapacitor industry is expected to experience significant growth in the next three to five years. However, with the increasing demand for high energy density, high power density, and long cycle life capacitor materials, traditional capacitor carbons are gradually exposing limitations such as insufficient specific surface area, unstable capacitance performance, and poor structural strength.

[0003] Traditional capacitor carbon has achieved certain applications in the field of electrochemical energy storage, but there are still some significant problems. First, the sources of natural organic matter or synthetic organic matter as raw materials are limited, the supply is unstable and the cost is high. Secondly, the structural strength of traditional capacitor carbon is poor, resulting in unstable capacitance performance, deformation or breakage during rapid charging and discharging, affecting the stability and life of electrochemical energy storage equipment. Spherical capacitor carbon has high strength and can solve the above problems. Finally, the synthesis process such as template method and solution polymerization is complex, polluting and costly, making it difficult to achieve large-scale industrial production.

[0004] Therefore, it is necessary to develop an efficient, low-cost and environmentally friendly template synthesis method to ensure the uniformity, stability and controllability of the pore structure of capacitive carbon. Summary of the Invention

[0005] The present invention aims to solve one of the technical problems in the related art to at least a certain extent. To this end, an embodiment of the present invention provides a method for preparing hollow spherical capacitor carbon based on coal tar pitch.

[0006] The method for preparing hollow spherical capacitor carbon based on coal tar pitch according to an embodiment of the present invention comprises the following steps:

[0007] (1) crushing coal tar pitch and grinding and mixing with naphthalene to form a pitch powder, and then stirring with a solvent under heating conditions to obtain a first mixed solution;

[0008] (2) dissolving the template in n-butanol and adding the mixture to the first mixed solution prepared in step (1), and then adding a dispersant and stirring and dissolving the mixture under heating conditions to obtain a second mixed solution;

[0009] (3) cooling the second mixed solution obtained in step (2) to room temperature, performing reduced pressure distillation to obtain a coal tar pitch containing a template, and performing annealing and carbonization treatment to obtain a carbonized sample;

[0010] (4) adding an excess of dilute hydrochloric acid solution to the carbonized sample obtained in step (3) and stirring to remove the template, followed by washing and vacuum drying;

[0011] (5) Activating the sample obtained in step (4) to obtain hollow spherical capacitor carbon.

[0012] The advantages and technical effects brought by the preparation method of hollow spherical capacitor carbon based on coal tar of the embodiment of the present invention are as follows: 1. The method of the embodiment of the present invention uses a stable supply of coal tar (coal liquefaction tar, coal tar tar, high-temperature coal tar, etc.) as raw material to reduce the production cost of spherical capacitor carbon; 2. The method of the embodiment of the present invention uses aluminum isopropoxide as a template and prepares a suitable spherical carbon precursor by adding a dispersant; 3. The method of the embodiment of the present invention elutes the template through a pickling process and removes ash and impurities in the raw material at the same time; through carbonization / activation, the specific surface area and microporosity of the capacitor carbon are increased; 4. The hollow capacitor carbon material prepared by the method of the embodiment of the present invention has a high specific surface area and a special pore structure, which meets the application requirements of supercapacitors in the new energy storage and GPU industries.

[0013] In some embodiments, in step (1), the coal tar pitch includes at least one of coal liquefaction pitch, coal tar pitch, or high-temperature coal tar pitch, and the crushing treatment time is 3 to 8 minutes to ensure that the raw material particle size is greater than 300 mesh;

[0014] And / or, in the step (1), the amount of naphthalene added is 5 to 15 wt% of the coal tar pitch;

[0015] And / or, in step (1), the solvent includes at least one of toluene, xylene, tetrahydrofuran or pyridine, and the liquid-to-solid ratio of the solvent to coal tar is 100-200 mL / 50 g.

[0016] In some embodiments, in step (1), the stirring treatment is carried out under N2 protection, and the flow rate of N2 is 30 to 60 mL / min;

[0017] And / or, in the step (1), the stirring temperature is 160-200° C., the stirring speed is 80-120 r / min, and the stirring time is 15-45 min.

[0018] In some embodiments, in step (2), the template comprises at least one of aluminum isopropoxide, silica, or magnesium oxide, the mass ratio of the template to coal tar is 1:(1-2), and the liquid-to-solid ratio of n-butanol to the template is 150-200 mL / 50 g;

[0019] And / or, in step (2), the dispersant includes at least one of PVP, CTAB, CTAC, SDBS or (NaPO3)6, and the added amount of the dispersant is 5 to 20 wt% of the mass of the coal tar.

[0020] In some embodiments, in step (2), the stirring and dissolving temperature is 180-240° C., the stirring and dissolving speed is 100-300 r / min, and the stirring and dissolving time is 1-3 h;

[0021] And / or, in the step (2), the stirring and dissolving is carried out under N2 protection, and the flow rate of N2 is 30 to 60 mL / min.

[0022] In some embodiments, in step (3), the annealing treatment time is 150-250° C., the heating rate is 0.5-2° C. / min, the annealing treatment time is 1-4 h, and the annealing treatment is performed in a muffle furnace;

[0023] And / or, in the step (3), the carbonization treatment is carried out in a high-temperature tube furnace, the carbonization treatment is carried out under a N2 atmosphere, and the flow rate of N2 is 20 to 50 mL / min;

[0024] And / or, in step (3), the temperature of the carbonization treatment is 1200-1800° C., the heating rate is 5-10° C. / min, and the carbonization treatment time is 1-3 hours.

[0025] In some embodiments, in step (4), the concentration of the dilute hydrochloric acid solution is 0.5 to 3 mol / L, the stirring temperature is 1 to 5° C., and the stirring time is 2 to 3 hours;

[0026] And / or, in the step (4), the washing treatment comprises washing with ethanol and deionized water;

[0027] And / or, in the step (4), the temperature of the vacuum drying treatment is 60 to 90° C., and the time of the vacuum drying treatment is 10 to 15 hours.

[0028] In some embodiments, in step (5), the activation treatment is performed in a mixed atmosphere of N2 and water vapor, wherein the flow rate of N2 is 15 to 45 mL / min and the flow rate of water vapor is 3 to 5 mL / h;

[0029] And / or, in step (5), the activation treatment temperature is 800-1200° C., the heating rate is 3-7° C. / min, and the activation treatment time is 1-2 h.

[0030] The embodiment of the present invention further provides a hollow spherical capacitor carbon based on coal tar pitch, which is prepared using the above-mentioned preparation method.

[0031] The embodiments of the present invention also provide the hollow spherical capacitor carbon based on coal tar pitch prepared by the above preparation method or the use of the above hollow spherical capacitor carbon based on coal tar pitch in a supercapacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the process for preparing hollow spherical capacitor carbon;

[0033] Figure 2 2 is a graph showing the N2 adsorption-desorption curves of the hollow spherical capacitor carbons prepared in Example 1 and Comparative Examples 1 to 3;

[0034] Figure 3 is a pore size distribution diagram of the hollow spherical capacitor carbons prepared in Example 1 and Comparative Examples 1 to 3;

[0035] Figure 4 1 is the X-ray diffraction spectrum of the hollow spherical capacitor carbon prepared in Example 1 and Comparative Examples 1 to 3;

[0036] Figure 5 1 is a Raman spectrum of the hollow spherical capacitor carbons prepared in Example 1 and Comparative Examples 1 to 3;

[0037] Figure 6 1 is a thermogravimetric analysis curve of the hollow spherical capacitor carbon prepared in Example 1 and Comparative Examples 1 to 3;

[0038] Figure 7 1 is an infrared spectrum of the hollow spherical capacitor carbons prepared in Examples 1 to 3 and Comparative Examples 1 to 3;

[0039] Figure 8 is a transmission electron microscope image of the hollow spherical capacitor carbon prepared in Example 1;

[0040] Figure 9 is a transmission electron microscope image of the hollow spherical capacitor carbon prepared in Example 2;

[0041] Figure 10 is a transmission electron microscope image of the hollow spherical capacitor carbon prepared in Example 3;

[0042] Figure 11 1 is a scanning electron microscope image of the hollow spherical capacitor carbon prepared in Example 1 and Comparative Examples 1 to 3;

[0043] Figure 12 The cyclic voltammetry curves of the electrodes prepared in Examples 4 and 5 and Comparative Example 4 at a scan rate of 5-50 mV / s are shown;

[0044] Figure 13 It is a charge and discharge curve diagram of the electrodes prepared in Examples 4-5 and Comparative Example 4 under 1 A / g conditions. DETAILED DESCRIPTION

[0045] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0046] like Figure 1 As shown, the method for preparing hollow spherical capacitor carbon based on coal tar pitch according to an embodiment of the present invention comprises the following steps:

[0047] (1) crushing coal tar pitch and grinding and mixing with naphthalene to form a pitch powder, and then stirring with a solvent under heating conditions to obtain a first mixed solution;

[0048] (2) dissolving the template in n-butanol and adding the mixture to the first mixed solution prepared in step (1), and then adding a dispersant and stirring and dissolving the mixture under heating conditions to obtain a second mixed solution;

[0049] (3) cooling the second mixed solution obtained in step (2) to room temperature, performing reduced pressure distillation to obtain a coal tar pitch containing a template, and performing annealing and carbonization treatment to obtain a carbonized sample;

[0050] (4) adding an excess of dilute hydrochloric acid solution to the carbonized sample obtained in step (3) and stirring to remove the template, followed by washing and vacuum drying;

[0051] (5) Activating the sample obtained in step (4) to obtain hollow spherical capacitor carbon.

[0052] The preparation method of hollow spherical capacitor carbon based on coal tar in an embodiment of the present invention uses a stable supply of coal tar (coal liquefaction tar, coal tar tar, high-temperature coal tar, etc.) as raw material to reduce the production cost of spherical capacitor carbon; the method of the embodiment of the present invention uses aluminum isopropoxide as a template and prepares a suitable spherical carbon precursor by adding a dispersant; the method of the embodiment of the present invention elutes the template through a pickling process and removes ash and impurities in the raw material at the same time; through carbonization / activation, the specific surface area and microporosity of the capacitor carbon are increased; the hollow capacitor carbon material prepared by the method of the embodiment of the present invention has a high specific surface area and a special pore structure, which meets the application requirements of supercapacitors in the new energy storage and GPU industries.

[0053] In some embodiments, preferably, in step (1), the coal tar pitch includes at least one of coal liquefaction pitch, coal tar pitch or high-temperature coal tar pitch, and the crushing treatment time is 3 to 8 minutes to ensure that the raw material particle size is greater than 300 mesh;

[0054] And / or, in the step (1), the amount of naphthalene added is 5 to 15 wt% of the coal tar pitch, for example, 5 wt%, 7 wt%, 9 wt%, 11 wt%, 13 wt% or 15 wt%;

[0055] And / or, in step (1), the solvent includes at least one of toluene, xylene, tetrahydrofuran or pyridine, and the liquid-to-solid ratio of the solvent to coal tar is 100-200 mL / 50 g.

[0056] In some embodiments, preferably, in step (1), the stirring treatment is carried out under N2 protection, and the N2 flow rate is 30 to 60 mL / min, such as 30, 40, 50 or 60 mL / min;

[0057] And / or, in the step (1), the stirring temperature is 160-200° C., the stirring speed is 80-120 r / min, and the stirring time is 15-45 min.

[0058] In some embodiments, preferably, in step (2), the template comprises at least one of aluminum isopropoxide, silicon dioxide or magnesium oxide, the mass ratio of the template to coal tar is 1:(1-2), for example, 1:1, 1:1.5 or 1:2, and the liquid-solid ratio of the n-butanol to the template is 150-200 mL / 50 g;

[0059] And / or, in step (2), the dispersant includes at least one of PVP, CTAB, CTAC, SDBS or (NaPO3)6, and the amount of the dispersant added is 5 to 20 wt% of the mass of the coal tar, for example, 5 wt%, 6 wt%, 8 wt%, 10 wt%, 12 wt%, 14 wt%, 16 wt%, 18 wt% or 20 wt%.

[0060] In some embodiments, preferably, in step (2), the stirring and dissolving temperature is 180-240° C., the stirring and dissolving speed is 100-300 r / min, and the stirring and dissolving time is 1-3 h;

[0061] And / or, in the step (2), the stirring and dissolving is carried out under N2 protection, and the flow rate of N2 is 30 to 60 mL / min.

[0062] In some embodiments, preferably, in the step (3), the annealing treatment time is 150-250°C, for example, 150°C, 170°C, 190°C, 210°C, 230°C or 250°C, etc., the heating rate is 0.5-2°C / min, for example, 0.5°C / min, 1°C / min, 1.5°C / min or 2°C / min, etc., the annealing treatment time is 1-4h, for example, 1h, 2h, 3h or 4h, and the annealing treatment is carried out in a muffle furnace.

[0063] In the embodiment of the present invention, annealing treatment can improve the stability of the template-containing coal tar balls, prevent the carbon balls from sticking together or melting together during the subsequent carbonization process, and further optimize the annealing conditions. If the annealing temperature is too high or the treatment time is too long, the oxygen content of the carbon balls will be too high, thereby reducing the conductivity of the final capacitive carbon sample. If the annealing temperature is too low or the treatment time is too short, the pre-oxidation effect is insufficient, and adhesion or melting will still occur during the subsequent carbonization process.

[0064] In some embodiments, preferably, in step (3), the carbonization treatment is carried out in a high-temperature tube furnace, and the carbonization treatment is carried out under a N2 atmosphere with an N2 flow rate of 20 to 50 mL / min, for example, 20, 30, 40 or 50 mL / min;

[0065] And / or, in step (3), the temperature of the carbonization treatment is 1200-1800°C, for example, 1200°C, 1300°C, 1400°C, 1500°C, 1600°C, 1700°C or 1800°C, etc., the heating rate is 5-10°C / min, for example, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min or 10°C / min, etc., and the carbonization treatment time is 1-3h, 1h, 2h or 3h, etc.

[0066] In the embodiment of the present invention, the carbonization treatment is carried out to remove non-carbon components, retain the carbon-containing skeleton, form a basic pore structure, lay the foundation for increasing the specific surface area and pore volume in the subsequent activation process, and improve the mechanical strength. The conditions of the carbonization treatment are further optimized. If the temperature of the carbonization treatment is too high or the treatment time is too long, the carbonized sample will have fewer voids, which is not conducive to subsequent activation. If the temperature of the carbonization treatment is too low or the treatment time is too short, the carbonization is insufficient, which affects the conductive properties of the final product.

[0067] In some embodiments, preferably, in step (4), the concentration of the dilute hydrochloric acid solution is 0.5 to 3 mol / L, such as 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L or 3 mol / L, etc., the stirring temperature is 1 to 5°C, such as 1°C, 2°C, 3°C, 4°C or 5°C, etc., and the stirring time is 2 to 3 h, such as 2 h, 2.5 h or 3 h, etc.;

[0068] And / or, in the step (4), the washing treatment comprises washing with ethanol and deionized water;

[0069] And / or, in step (4), the temperature of the vacuum drying treatment is 60-90°C, for example, 60°C, 70°C, 80°C or 90°C, and the time of the vacuum drying treatment is 10-15h, for example, 10h, 11h, 12h, 13h, 14h or 15h.

[0070] In some embodiments, preferably, in step (5), the activation treatment is carried out in a mixed atmosphere of N2 and water vapor, wherein the flow rate of N2 is 15 to 45 mL / min, such as 15 mL / min, 20 mL / min, 25 mL / min, 30 mL / min, 35 mL / min, 40 mL / min or 45 mL / min, and the flow rate of water vapor is 3 to 5 mL / h, such as 3 mL / h, 4 mL / h or 5 mL / h;

[0071] And / or, in step (5), the temperature of the activation treatment is 800-1200°C, for example, 800°C, 900°C, 1000°C, 1100°C or 1200°C, the heating rate is 3-7°C / min, for example, 3°C / min, 4°C / min, 5°C / min, 6°C / min or 7°C / min, and the activation treatment time is 1-2h, for example, 1h, 1.5h or 2h.

[0072] In the embodiment of the present invention, activation treatment is performed to increase the specific surface area and pore volume, accurately control the pore size range, and further optimize the conditions of the activation treatment. If the temperature of the activation treatment is too high or the treatment time is too long, the product yield is reduced, the pores are excessively formed, and the pore size becomes larger. If the temperature of the activation treatment is too low or the treatment time is too short, the activation effect is insufficient, and the specific surface area and pore volume are small. If the flow rate of water vapor is too large, excessive activation will occur. If the flow rate of water vapor is too small, insufficient activation will occur.

[0073] The embodiment of the present invention further provides a hollow spherical capacitor carbon, which is prepared by the above-mentioned preparation method.

[0074] The embodiments of the present invention further provide the hollow spherical capacitor carbon prepared by the above preparation method or the use of the above hollow spherical capacitor carbon in a supercapacitor.

[0075] The technical solution of the present invention is described in detail below with reference to specific embodiments and drawings.

[0076] Example 1

[0077] (1) Weigh 50 g of coal liquefaction pitch, crush it in a crusher for 5 min, add 10 wt % of naphthalene to lower the softening point, grind and mix to form pitch powder, and ensure that the particle size of the pitch powder is greater than 300 mesh;

[0078] (2) Add asphalt powder and 100 mL of toluene into a three-necked flask protected by N2 at a N2 flow rate of 50 mL / min, heat to 200°C, and stir at 100 rpm for 35 minutes to obtain a first mixed solution;

[0079] (3) Add aluminum isopropoxide as a template into a beaker containing 150 mL of n-butanol, with a mass ratio of template to coal liquefaction pitch of 1:1, and stir evenly for 30 minutes to fully dissolve;

[0080] (4) Slowly add n-butanol containing the template into a three-necked flask, then add the dispersant CTAB, the amount of which is 10 wt% of the mass of the coal liquefaction pitch, and stir and dissolve at 200 rpm for 2 h at 200 ° C under N2 protection to obtain a second mixed solution;

[0081] (5) After the stirring is completed and the mixture is cooled to room temperature, the coal liquefaction pitch containing aluminum isopropoxide is obtained by vacuum distillation, and the mixture is heated to 180°C at a rate of 2°C / min in a muffle furnace and annealed for 2 h;

[0082] (6) The dried sample was placed in a high-temperature tube furnace, protected by N2, with an N2 flow rate of 35 mL / min, a heating rate of 10 °C / min, and carbonized at 1500 °C for 2 h to obtain a carbonized sample;

[0083] (7) Add excess 1 mol / L dilute hydrochloric acid solution to the carbonized sample, stir at 3°C ​​for 3 h to remove the template, wash with ethanol and deionized water, and dry the washed sample in vacuum at 80°C for 12 h;

[0084] (8) The dried sample was placed in a high-temperature tube furnace with a nitrogen flow rate of 30 mL / min and a water vapor flow rate of 5 mL / h. The temperature was raised to 1000 °C at a heating rate of 5 °C / min and the activation treatment was performed for 1 h to obtain hollow spherical capacitor carbon.

[0085] Example 2

[0086] (1) Weigh 50 g of coal tar pitch, crush it in a crusher for 5 min, add 5 wt % of naphthalene to lower the softening point, grind and mix to form pitch powder, and ensure that the particle size of the pitch powder is greater than 300 mesh;

[0087] (2) Add asphalt powder and 100 mL of toluene into a three-necked flask protected by N2 at a N2 flow rate of 50 mL / min, heat to 180°C, and stir at a speed of 100 r / min for 25 min to obtain a first mixed solution;

[0088] (3) Add aluminum isopropoxide as a template into a beaker containing 120 mL of n-butanol, with a mass ratio of template to coal tar pitch of 1:1.5, and stir evenly for 30 minutes to fully dissolve;

[0089] (4) Slowly add n-butanol containing the template into a three-necked flask, then add the dispersant SDBS in an amount of 15 wt% of the coal tar pitch mass, and stir and dissolve at 180°C under N2 protection at 200 rpm for 1.5 h to obtain a second mixed solution;

[0090] (5) After stirring, the mixture was cooled to room temperature, and then the coal tar pitch containing aluminum isopropoxide was obtained by vacuum distillation, and the mixture was heated to 200°C at a rate of 1.5°C / min in a muffle furnace and annealed for 1 h;

[0091] (6) The dried sample was placed in a high-temperature tube furnace under N2 protection, with a flow rate of 50 mL / min, a heating rate of 5 °C / min, and a temperature of 1200 °C for carbonization treatment for 3 h to obtain a carbonized sample;

[0092] (7) Add excess 1 mol / L dilute hydrochloric acid solution to the carbonized sample, stir at 3°C ​​for 3 h to remove the template, wash with ethanol and deionized water, and dry the washed sample in vacuum at 80°C for 12 h;

[0093] (8) The dried sample was placed in a high-temperature tube furnace with a nitrogen flow rate of 35 mL / min, a water vapor flow rate of 3 mL / h, a heating rate of 5 °C / min, and the temperature was raised to 1000 °C. The activation treatment was performed for 2 h to obtain hollow spherical capacitor carbon.

[0094] Example 3

[0095] (1) Weighing 50 g of low-temperature coal tar pitch, crushing it in a crusher for 5 min, adding 8 wt % of naphthalene to lower the softening point, and grinding it to form asphalt powder, ensuring that the particle size of the asphalt powder is greater than 300 mesh;

[0096] (2) Add asphalt powder and 100 mL of toluene into a three-necked flask protected by N2 at a N2 flow rate of 50 mL / min, heat to 160°C, and stir at a speed of 100 r / min for 15 min to obtain a first mixed solution;

[0097] (3) Add aluminum isopropoxide as a template into a beaker containing 100 mL of n-butanol, with a mass ratio of template to low-temperature coal tar pitch of 1:2, and stir evenly for 30 minutes to fully dissolve;

[0098] (4) Slowly add n-butanol containing the template into a three-necked flask, then add a dispersant (NaPO3)6, the amount of which is 10 wt% of the mass of the low-temperature coal tar pitch, and stir and dissolve at 180°C under N2 protection at 200 r / min for 1.5 h to obtain a second mixed solution;

[0099] (5) After the stirring is completed and the mixture is cooled to room temperature, low-temperature coal tar pitch containing aluminum isopropoxide is obtained by vacuum distillation, and the mixture is heated to 150°C at a rate of 1°C / min in a muffle furnace and annealed for 2 h;

[0100] (6) The dried sample was placed in a high-temperature tube furnace under N2 protection, a flow rate of 45 mL / min, a heating rate of 10 °C / min, and carbonized at 1700 °C for 2 h to obtain a carbonized sample;

[0101] (7) Add excess 1 mol / L dilute hydrochloric acid solution to the carbonized sample, stir at 3°C ​​for 2 h to remove the template, wash with ethanol and deionized water, and dry the washed sample in vacuum at 80°C for 12 h;

[0102] (8) The dried sample was placed in a high-temperature tube furnace with a nitrogen flow rate of 30 mL / min, a water vapor flow rate of 2 mL / h, and a heating rate of 5 °C / min to 900 °C. The sample was activated for 2 h to obtain a hollow spherical capacitor carbon.

[0103] Example 4

[0104] (1) The hollow spherical capacitor carbon prepared in Example 1 was used as the electrode material of the supercapacitor.

[0105] (2) Use a punching die to cut a 14 mm diameter nickel foam, clean it with deionized water and ethanol ultrasonically, and weigh the mass of each piece of nickel foam; weigh the sample according to the mass ratio of capacitive carbon: conductive carbon black: polytetrafluoroethylene dispersion = 8:1:1, add appropriate amount of ethanol, and grind it repeatedly for 30 minutes until it becomes a viscous mud sample; evenly coat the sample on the nickel foam, cover it with another piece of nickel foam and compact it, vacuum dry it at 80℃ for 12 hours, press it at 5MPa for 5 minutes, and weigh the prepared electrode.

[0106] (3) The prepared electrode was used as the working electrode, the Pt electrode as the counter electrode, the Hg / HgO electrode (1 mol / L KOH) as the reference electrode, and 6 mol / L KOH as the electrolyte to test the capacitance performance.

[0107] Example 5

[0108] The hollow spherical capacitor carbon prepared in Example 2 was used as the supercapacitor electrode material, and the other steps were consistent with those in Example 4.

[0109] Comparative Example 1

[0110] (1) Weigh 50 g of coal liquefaction pitch, crush it in a crusher for 5 min, add 10 wt % of naphthalene to lower the softening point, grind and mix to form pitch powder, and ensure that the particle size of the pitch powder is greater than 300 mesh;

[0111] (2) Add asphalt powder and 100 mL of toluene into a three-necked flask protected by N2 at a N2 flow rate of 50 mL / min, heat to 200°C, and stir at 100 rpm for 35 minutes to obtain a first mixed solution;

[0112] (3) Add aluminum isopropoxide as a template into a beaker containing 150 mL of n-butanol, with a mass ratio of template to coal liquefaction pitch of 1:1, and stir evenly for 30 minutes to fully dissolve;

[0113] (4) Slowly add the n-butanol containing the template into a three-necked flask, stir and dissolve at 200 rpm for 2 h at 200 °C under N2 protection to obtain a second mixed solution;

[0114] (5) After the stirring is completed and the mixture is cooled to room temperature, the coal liquefaction pitch containing aluminum isopropoxide is obtained by vacuum distillation, and the mixture is heated to 180°C at a rate of 2°C / min in a muffle furnace and annealed for 2 h;

[0115] (6) The dried sample was placed in a high-temperature tube furnace, protected by N2, with an N2 flow rate of 35 mL / min, a heating rate of 10 °C / min, and carbonized at 1500 °C for 2 h to obtain a carbonized sample;

[0116] (7) Add excess 1 mol / L dilute hydrochloric acid solution to the carbonized sample, stir at 3°C ​​for 3 h to remove the template, wash with ethanol and deionized water, and dry the washed sample in vacuum at 80°C for 12 h;

[0117] (8) The dried sample was placed in a high-temperature tube furnace with a nitrogen flow rate of 30 mL / min and a water vapor flow rate of 5 mL / h. The temperature was raised to 1000 °C at a heating rate of 5 °C / min and the activation treatment was performed for 1 h to obtain hollow spherical capacitor carbon.

[0118] Comparative Example 2

[0119] (1) Weigh 50 g of coal liquefaction pitch, crush it in a crusher for 5 min, add 10 wt % of naphthalene to lower the softening point, grind and mix to form pitch powder, and ensure that the particle size of the pitch powder is greater than 300 mesh;

[0120] (2) Add asphalt powder and 100 mL of toluene into a three-necked flask protected by N2 at a N2 flow rate of 50 mL / min, heat to 200°C, and stir at 100 rpm for 35 minutes to obtain a first mixed solution;

[0121] (3) Add aluminum isopropoxide as a template into a beaker containing 150 mL of n-butanol, with a mass ratio of template to coal liquefaction pitch of 1:1, and stir evenly for 30 minutes to fully dissolve;

[0122] (4) Slowly add n-butanol containing the template into a three-necked flask, then add the dispersant CTAB, the amount of which is 10 wt% of the mass of the coal liquefaction pitch, and stir and dissolve at 200 rpm for 2 h at 200 ° C under N2 protection to obtain a second mixed solution;

[0123] (5) After the stirring is completed and the mixture is cooled to room temperature, the coal liquefaction pitch containing aluminum isopropoxide is obtained by vacuum distillation and then vacuum dried at 80°C for 6 hours;

[0124] (6) The dried sample was placed in a high-temperature tube furnace, protected by N2, with an N2 flow rate of 35 mL / min, a heating rate of 10 °C / min, and carbonized at 1500 °C for 2 h to obtain a carbonized sample;

[0125] (7) Add excess 1 mol / L dilute hydrochloric acid solution to the carbonized sample, stir at 3°C ​​for 3 h to remove the template, wash with ethanol and deionized water, and dry the washed sample in vacuum at 80°C for 12 h;

[0126] (8) The dried sample was placed in a high-temperature tube furnace with a nitrogen flow rate of 30 mL / min, a water vapor flow rate of 5 mL / h, and a heating rate of 5 °C / min to a temperature of 1000 °C. The activation treatment was performed for 1 h to obtain a hollow spherical capacitor carbon.

[0127] Comparative Example 3

[0128] (1) Weigh 50 g of coal liquefaction pitch, crush it in a crusher for 5 min, add 10 wt % of naphthalene to lower the softening point, grind and mix to form pitch powder, and ensure that the particle size of the pitch powder is greater than 300 mesh;

[0129] (2) Add asphalt powder and 100 mL of toluene into a three-necked flask protected by N2 at a N2 flow rate of 50 mL / min, heat to 200°C, and stir at 100 rpm for 35 minutes to obtain a first mixed solution;

[0130] (3) Add aluminum isopropoxide as a template into a beaker containing 150 mL of n-butanol, with a mass ratio of template to coal liquefaction pitch of 1:1, and stir evenly for 30 minutes to fully dissolve;

[0131] (4) Slowly add n-butanol containing the template into a three-necked flask, then add the dispersant CTAB, the amount of which is 10 wt% of the mass of the coal liquefaction pitch, and stir and dissolve at 200 rpm for 2 h at 200 ° C under N2 protection to obtain a second mixed solution;

[0132] (5) After the stirring is completed and the mixture is cooled to room temperature, the coal liquefaction pitch containing aluminum isopropoxide is obtained by vacuum distillation, and the mixture is heated to 180°C at a rate of 2°C / min in a muffle furnace and annealed for 2 h;

[0133] (6) The dried sample was placed in a high-temperature tube furnace, protected by N2, with an N2 flow rate of 35 mL / min, a heating rate of 10 °C / min, and carbonized at 1500 °C for 2 h to obtain a carbonized sample;

[0134] (7) Add an excess of 1 mol / L dilute hydrochloric acid solution to the carbonized sample, stir at 3 °C for 3 h to remove the template, wash it with ethanol and deionized water, and vacuum dry the washed sample at 80 °C for 12 h to obtain hollow spherical capacitor carbon.

[0135] Comparative Example 4

[0136] (1) The hollow spherical capacitor carbon prepared in Comparative Example 1 was used as the electrode material of the supercapacitor.

[0137] (2) Use a punching die to cut a 14 mm diameter nickel foam, clean it with deionized water and ethanol ultrasonically, and weigh the mass of each piece of nickel foam; weigh the sample according to the mass ratio of capacitive carbon: conductive carbon black: polytetrafluoroethylene dispersion = 8:1:1, add appropriate amount of ethanol, and grind it repeatedly for 30 minutes until it becomes a viscous mud sample; evenly coat the sample on the nickel foam, cover it with another piece of nickel foam and compact it, vacuum dry it at 80℃ for 12 hours, press it at 5MPa for 5 minutes, and weigh the prepared electrode.

[0138] (3) The prepared electrode was used as the working electrode, the Pt electrode was used as the counter electrode, the Hg / HgO electrode (1 mol / L KOH) was used as the reference electrode, and 6 mol / L KOH was used as the electrolyte. The capacitance performance of the sample of Comparative Example 1 was tested.

[0139] The hollow spherical capacitor carbons prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were tested, and the results are shown in Table 1.

[0140] Table 1

[0141] <![CDATA[Specific surface area (m 2 / g)]]> Average pore size (nm) <![CDATA[Pore volume (cm 3 / g)]]> Microporosity (%) Thermal decomposition temperature (℃) Example 1 1786 2.0 1.04 59 >800 Example 2 1745 2.4 0.98 62 >800 Example 3 1639 2.2 0.91 60 >800 Comparative Example 1 1218 8.0 1.67 38 >800 Comparative Example 2 1043 7.8 1.79 35 >750 Comparative Example 3 627 15.1 0.71 29 >700

[0142] As can be seen from the above table, the specific surface area of ​​the hollow spherical capacitor carbon prepared by the method of the embodiment of the present invention is greater than 1600m 2 / g, which are all higher than those of the comparative samples. In Comparative Example 1, no dispersant was added, resulting in large size and average pore size of the hollow carbon spheres formed, which is not conducive to further carbonization / activation treatment; Comparative Example 2 did not undergo annealing treatment, resulting in unstable spherical structure of the sample and adhesion and melting during the carbonization process; Comparative Example 3 did not undergo steam activation treatment, resulting in a low specific surface area, large average pore size and low thermal decomposition temperature of the hollow spherical capacitor carbon prepared.

[0143] like Figure 2 As shown in Figure 2, the hollow spherical capacitor carbon prepared in Example 1 has the highest specific surface area, which is 1786 m 2 / g, which are higher than those of samples 1-3 in comparative examples (627-1218 m 2 / g). The adsorption-desorption curves of the hollow spherical capacitor carbon prepared in Example 1 all belong to type IV isotherms, indicating that the material is mainly composed of micropores and mesopores, while the hollow spherical capacitor carbons prepared in Comparative Examples 1 to 3 have lower microporosity and specific surface area and poor molecular adsorption capacity.

[0144] like Figure 3 As shown, the pore size of the hollow spherical capacitor carbon prepared in Example 1 is 2.0 nm, which is lower than the pore size of the hollow spherical capacitor carbon prepared in Comparative Examples 1 to 3, indicating that dispersion assistance, annealing treatment and water vapor activation treatment will reduce the pore size.

[0145] like Figure 4 As shown, the hollow spherical capacitor carbons prepared in Example 1 and Comparative Examples 1 to 3 are all amorphous materials, and have obvious (002) and (100) diffraction peaks.

[0146] like Figure 5 As shown, the hollow spherical capacitor carbons prepared in Example 1 and Comparative Examples 1 to 3 all have a 1350 cm -1 and 1590cm -1 There are two typical D peaks and G peaks nearby. According to I D / I G The value indicates the degree of graphitization. Example 1 Sample I D / I G The value is 0.89, which has the highest degree of graphitization.

[0147] like Figure 6 As shown, the thermal decomposition temperature of the hollow spherical capacitor carbon prepared in Example 1 is greater than 800°C, showing good thermal stability. Since the samples in Comparative Examples 2 and 3 were not annealed or subjected to steam activation treatment, their thermal decomposition temperatures are relatively low.

[0148] like Figure 7 As shown, the hollow spherical capacitor carbons prepared in Examples 1 to 3 and Comparative Examples 1 to 3 all have OH, CH, C=C, CO, COC, and -CH3 carbon material characteristic peak functional groups.

[0149] like Figure 8-10 , which are transmission electron micrographs of samples from Examples 1 to 3. The hollow spherical capacitor carbons prepared in all Examples have spherical morphologies and hollow structures. Due to the graphitization treatment at >1800°C, they show obvious lattice fringes under high-magnification transmission electron microscopy.

[0150] like Figure 11 As shown, the hollow spherical capacitor carbon prepared in Example 1 has a spherical morphology with a particle size of 1 to 3 μm. The sample in Comparative Example 1 does not add a dispersant, and the spherical morphology is poorly formed; the sample in Comparative Example 2 is not annealed, and melting occurs during the carbonization process.

[0151] like Figure 12 and 13 As shown, the electrodes prepared using Examples 4 and 5 have the highest specific capacitance in the supercapacitor, with a specific capacitance of >70F / g at a scan rate of 5mV / s, which is higher than all the electrodes in Comparative Example 4. At the same time, after 100 cycles, the performance of the electrodes in Examples 4 and 5 still maintains 85% of the capacitance performance, indicating that the hollow spherical conductive carbon has excellent capacitance performance and operational stability.

[0152] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0153] Although the above embodiments have been shown and described, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those skilled in the art are all within the scope of protection of the present invention.

Claims

1. A method for preparing hollow spherical capacitor carbon based on coal tar pitch, characterized in that: The following steps are involved: (1) crushing coal tar pitch and grinding and mixing with naphthalene to form a pitch powder, and then stirring with a solvent under heating conditions to obtain a first mixed solution; (2) dissolving the template in n-butanol and adding the mixture to the first mixed solution prepared in step (1), and then adding a dispersant and stirring and dissolving the mixture under heating conditions to obtain a second mixed solution; (3) cooling the second mixed solution obtained in step (2) to room temperature, performing reduced pressure distillation to obtain a coal tar pitch containing a template, and performing annealing and carbonization treatment to obtain a carbonized sample; (4) adding an excess of dilute hydrochloric acid solution to the carbonized sample obtained in step (3) and stirring to remove the template, followed by washing and vacuum drying; (5) Activating the sample obtained in step (4) to obtain hollow spherical capacitor carbon.

2. The method for preparing hollow spherical capacitor carbon based on coal tar pitch according to claim 1, characterized in that: In the step (1), the coal tar pitch includes at least one of coal liquefaction pitch, coal tar pitch or high-temperature coal tar pitch, and the crushing treatment time is 3 to 8 minutes to ensure that the raw material particle size is greater than 300 mesh; And / or, in the step (1), the amount of naphthalene added is 5 to 15 wt% of the coal tar pitch; And / or, in step (1), the solvent includes at least one of toluene, xylene, tetrahydrofuran or pyridine, and the liquid-to-solid ratio of the solvent to coal tar is 100-200 mL / 50 g.

3. The method for preparing hollow spherical capacitor carbon based on coal tar pitch according to claim 1 or 2, characterized in that: In the step (1), the stirring treatment is carried out under N2 protection, and the flow rate of N2 is 30 to 60 mL / min; And / or, in the step (1), the stirring temperature is 160-200° C., the stirring speed is 80-120 r / min, and the stirring time is 15-45 min.

4. The method for preparing hollow spherical capacitor carbon based on coal tar pitch according to claim 1, characterized in that: In the step (2), the template comprises at least one of aluminum isopropoxide, silicon dioxide or magnesium oxide, the mass ratio of the template to coal tar is 1:(1-2), and the liquid-to-solid ratio of the n-butanol to the template is 150-200 mL / 50 g; And / or, in step (2), the dispersant includes at least one of PVP, CTAB, CTAC, SDBS or (NaPO3)6, and the added amount of the dispersant is 5 to 20 wt% of the mass of the coal tar.

5. The method for preparing hollow spherical capacitor carbon based on coal tar pitch according to claim 1 or 4, characterized in that: In the step (2), the temperature of the stirring and dissolving is 180 to 240° C., the speed of the stirring and dissolving is 100 to 300 r / min, and the time of the stirring and dissolving is 1 to 3 hours; And / or, in the step (2), the stirring and dissolving is carried out under N2 protection, and the flow rate of N2 is 30 to 60 mL / min.

6. The method for preparing hollow spherical capacitor carbon based on coal tar pitch according to claim 1, characterized in that: In the step (3), the annealing treatment time is 150-250° C., the heating rate is 0.5-2° C. / min, the annealing treatment time is 1-4 hours, and the annealing treatment is carried out in a muffle furnace; And / or, in the step (3), the carbonization treatment is carried out in a high-temperature tube furnace, the carbonization treatment is carried out under a N2 atmosphere, and the flow rate of N2 is 20 to 50 mL / min; And / or, in step (3), the temperature of the carbonization treatment is 1200-1800° C., the heating rate is 5-10° C. / min, and the carbonization treatment time is 1-3 hours.

7. The method for preparing hollow spherical capacitor carbon based on coal tar pitch according to claim 1, characterized in that: In the step (4), the concentration of the dilute hydrochloric acid solution is 0.5 to 3 mol / L, the stirring temperature is 1 to 5°C, and the stirring time is 2 to 3 hours; And / or, in the step (4), the washing treatment comprises washing with ethanol and deionized water; And / or, in the step (4), the temperature of the vacuum drying treatment is 60 to 90° C., and the time of the vacuum drying treatment is 10 to 15 hours.

8. The method for preparing hollow spherical capacitor carbon based on coal tar pitch according to claim 1, characterized in that: In the step (5), the activation treatment is carried out in a mixed atmosphere of N2 and water vapor, wherein the flow rate of N2 is 15 to 45 mL / min and the flow rate of water vapor is 3 to 5 mL / h; And / or, in step (5), the activation treatment temperature is 800-1200° C., the heating rate is 3-7° C. / min, and the activation treatment time is 1-2 h.

9. A hollow spherical capacitor carbon based on coal tar pitch, characterized in that: The method is prepared according to any one of claims 1 to 8.

10. Use of the coal tar pitch-based hollow spherical capacitor carbon prepared by the preparation method according to any one of claims 1 to 8 or the coal tar pitch-based hollow spherical capacitor carbon according to claim 9 in supercapacitors.

Images