Small-size phenolic resin-based carbon microspheres as well as preparation method and application thereof

Abstract

The invention relates to small-size phenolic resin-based carbon microspheres as well as a preparation method and application thereof. The preparation method of the small-size phenolic resin-based carbon microspheres comprises the steps that water-insoluble thermosetting liquid phenolic resin, a curing agent, a dispersing agent and water are mixed to obtain oil-in-water emulsion, the mass ratio of the water-insoluble thermosetting liquid phenolic resin to the water is 1: 21-1: 25, and the mass ratio of the water-insoluble thermosetting liquid phenolic resin to the dispersing agent is 1: 1-2: 1; adding an acid catalyst into the oil-in-water emulsion, and then carrying out thermocuring to obtain phenolic resin microspheres; the phenolic resin microspheres are carbonized to obtain the small-size phenolic resin-based carbon microspheres, the average particle size of the small-size phenolic resin-based carbon microspheres is 0.5-2 microns, the specific surface area of the small-size phenolic resin-based carbon microspheres is 500-600 m < 2 > / g, and the tap density of the small-size phenolic resin-based carbon microspheres is 0.55-0.6 g / cm < 3 >. The preparation method is safe, stable, simple in equipment and low in cost, and meanwhile, the prepared small-size phenolic resin-based carbon microspheres are small in size, uniform in particle size and high in stacking density and can be well applied to preparation of activated carbon, catalyst carriers and electrode materials.

Description

Technical Field

[0001] The invention relates to the technical field of carbon materials, and in particular to small-sized phenolic resin-based carbon microspheres and a preparation method and application thereof. Background Art

[0002] Phenolic resin-based carbon microspheres are widely used in activated carbon preparation, catalyst carriers, supercapacitor electrode materials and other fields due to their excellent conductivity and chemical stability.

[0003] At present, the preparation methods of phenolic resin-based carbon microspheres mainly include synthesis method, precipitation method, emulsification method and spray drying method. Among them, the raw materials used in the existing synthesis method contain carcinogens such as formaldehyde, and the preparation process is relatively dangerous; the existing precipitation method, although it can avoid the use of carcinogens such as formaldehyde, requires nucleation and solidification precipitation in an acidic and high-temperature environment, the required curing temperature is high, and the microsphere size is large; and the existing emulsification method mostly requires high-temperature and high-pressure equipment such as hydrothermal reactors, or requires a long curing time, which is not conducive to industrial production; the spray drying method has complex equipment and occupies a large space.

[0004] In addition, most of the phenolic resin-based carbon microspheres prepared by existing preparation methods are large in size and have low packing density, and cannot be well applied in the fields of supercapacitor electrode materials. Summary of the invention

[0005] Based on this, it is necessary to provide a small-sized phenolic resin-based carbon microsphere and its preparation method and application for the above-mentioned problems. The preparation method is safe and stable, the equipment is simple, the cost is low, and the prepared small-sized phenolic resin-based carbon microspheres are small in size, uniform in particle size, and high in bulk density, and can be well applied to the preparation of activated carbon, catalyst carriers, and supercapacitor electrode materials.

[0006] A method for preparing small-sized phenolic resin-based carbon microspheres comprises the following steps:

[0007] Mixing a water-insoluble thermosetting liquid phenolic resin, a curing agent, a dispersant and water to obtain an oil-in-water emulsion, wherein the mass ratio of the water-insoluble thermosetting liquid phenolic resin to the water is 1:21-1:25, and the mass ratio of the water-insoluble thermosetting liquid phenolic resin to the dispersant is 1:1-2:1;

[0008] adding an acidic catalyst to the oil-in-water emulsion, and then performing thermal curing to obtain phenolic resin microspheres;

[0009] The phenolic resin microspheres are carbonized to obtain small-sized phenolic resin-based carbon microspheres, wherein the small-sized phenolic resin-based carbon microspheres have an average particle size of 0.5 μm-2 μm and a specific surface area of ​​500 m 2 / g-600m 2 / g, tap density is 0.55g / cm 3 -0.6g / cm 3 .

[0010] In one embodiment, in the step of adding an acidic catalyst to the oil-in-water emulsion, an acidic emulsion is obtained, and the pH of the acidic emulsion is ≤ 0.25.

[0011] In one embodiment, the mass ratio of the water-insoluble thermosetting liquid phenolic resin to the curing agent is 2:1-10:1;

[0012] And / or, the mass ratio of the water-insoluble thermosetting liquid phenolic resin to the acidic catalyst is 1:1.2-1:1.6.

[0013] In one embodiment, the curing agent is selected from at least one of sodium bicarbonate, propylene carbonate, and vinyl acetate;

[0014] And / or, the dispersant is selected from at least one of sodium dodecylbenzene sulfonate, dodecyltrimethylammonium chloride and polyvinyl alcohol;

[0015] And / or, the acidic catalyst is selected from at least one of hydrochloric acid and nitric acid.

[0016] In one embodiment, in the step of mixing the non-water-soluble thermosetting liquid phenolic resin, the curing agent, the dispersant and the water, the mixing temperature is 20° C.-50° C. and the mixing time is 5 min-30 min;

[0017] And / or, in the step of adding the acidic catalyst to the oil-in-water emulsion, the mixing time is 5 min to 20 min.

[0018] In one embodiment, the thermal curing temperature is 80° C.-100° C., and the thermal curing time is 0.5 h-5 h.

[0019] In one embodiment, after thermal curing, centrifugation, washing and drying are further performed to obtain phenolic resin microspheres, wherein the drying temperature is 60° C.-80° C. and the drying time is 10 h-24 h.

[0020] In one embodiment, in the step of carbonizing the phenolic resin microspheres, the protective atmosphere is selected from a nitrogen atmosphere and / or an inert gas atmosphere, the carbonization temperature is 600°C-900°C, the heating rate is 1°C / min-10°C / min, and the carbonization time is 0.5h-3h.

[0021] A small-sized phenolic resin-based carbon microsphere prepared by the method for preparing small-sized phenolic resin-based carbon microspheres as described above.

[0022] An application of the small-sized phenolic resin-based carbon microspheres as described above in activated carbon, catalyst carrier or supercapacitor electrode material.

[0023] In the preparation method of small-sized phenolic resin-based carbon microspheres of the present invention, the "mutually immiscible" characteristics of non-water-soluble thermosetting liquid phenolic resin and water are utilized to make the non-water-soluble thermosetting liquid phenolic resin self-spheroidize in water to form microspheres, and evenly disperse under the action of a dispersant to form a uniform and stable oil-in-water emulsion; at the same time, by adjusting the mass ratio of the non-water-soluble thermosetting liquid phenolic resin and water, the collision probability between the microspheres in the oil-in-water emulsion is reduced, thereby avoiding the generation of large-sized microspheres; and by adjusting the mass ratio of the non-water-soluble thermosetting liquid phenolic resin and the dispersant, the microspheres are evenly dispersed in water, which can further reduce the collision and merging between the microspheres, and then the microspheres in the oil-in-water emulsion are cured under the joint influence of an acid catalyst, a curing agent and thermal curing, and then carbonized to obtain small-sized phenolic resin-based carbon microspheres with a small size and uniform particle size. In addition, the present invention can promote the curing of microspheres by adding an acidic catalyst, reduce the curing temperature, and do not require high-temperature or high-pressure equipment, thereby reducing energy consumption, making the preparation method safe and stable, with simple equipment and low cost.

[0024] Therefore, the preparation method of the small-sized phenolic resin-based carbon microspheres of the present invention is safe and stable, the equipment is simple, and the cost is low. At the same time, the prepared small-sized phenolic resin-based carbon microspheres are small in size, uniform in particle size, and high in packing density, and can be well applied to the preparation of activated carbon, catalyst carriers or electrode materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 This is an electron microscope image of the small-sized phenolic resin-based carbon microspheres prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0027] For ease of understanding of the present invention, the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific implementation methods or embodiments, and are not intended to limit the present invention. The optional scope of the term "and / or" used herein includes any one of two or more related listed items, and also includes any and all combinations of related listed items, and the combinations include any two related listed items, any more related listed items, or all related listed items.

[0029] The method for preparing small-sized phenolic resin-based carbon microspheres provided by the present invention comprises the following steps:

[0030] S1, mixing a water-insoluble thermosetting liquid phenolic resin, a curing agent, a dispersant and water to obtain an oil-in-water emulsion, wherein the mass ratio of the water-insoluble thermosetting liquid phenolic resin to the water is 1:21-1:25, and the mass ratio of the water-insoluble thermosetting liquid phenolic resin to the dispersant is 1:1-2:1;

[0031] S2, adding an acidic catalyst to the oil-in-water emulsion, and then performing thermal curing to obtain phenolic resin microspheres;

[0032] S3, carbonizing the phenolic resin microspheres to obtain small-sized phenolic resin-based carbon microspheres, wherein the small-sized phenolic resin-based carbon microspheres have an average particle size of 0.5 μm-2 μm and a specific surface area of ​​500 m 2 / g-600m 2 / g, tap density is 0.55g / cm 3 -0.6g / cm 3 .

[0033] In the preparation method of small-sized phenolic resin-based carbon microspheres of the present invention, the "mutually immiscible" characteristics of the non-water-soluble thermosetting liquid phenolic resin and water are utilized. Under the action of surface tension, the non-water-soluble thermosetting liquid phenolic resin undergoes self-spheroidization to form microspheres in water, and is evenly dispersed under the action of a dispersant to form a uniform and stable water-in-oil emulsion.

[0034] Considering that collisions between microspheres will increase the size of the microspheres, in the present invention, by adjusting the mass ratio of the non-water-soluble thermosetting liquid phenolic resin and water, the probability of collisions between microspheres in the oil-in-water emulsion is reduced, thereby avoiding the generation of large-sized microspheres. In addition, by adjusting the mass ratio of the non-water-soluble thermosetting liquid phenolic resin and the dispersant, it is possible to ensure that the surface of the microspheres is attached with the dispersant, so that the microspheres are evenly dispersed in the water, further reducing the collision and merging between the microspheres.

[0035] Afterwards, an acid catalyst is added to the oil-in-water emulsion, so that the microspheres in the oil-in-water emulsion are cured under the combined influence of the acid catalyst, the curing agent and the thermal curing to form phenolic resin microspheres with an average particle size of 1 μm-2.5 μm, and then carbonized to obtain small-sized phenolic resin-based carbon microspheres with uniform particle size, and the average particle size of the small-sized phenolic resin-based carbon microspheres is 0.5 μm-2 μm, and the specific surface area is 500 m 2 / g-600m 2 / g, tap density is 0.55g / cm 3 -0.6g / cm 3 .

[0036] It should be noted that the average particle size of the small-sized phenolic resin-based carbon microspheres can be any value between 0.5 μm and 2 μm. Specifically, the average particle size of the small-sized phenolic resin-based carbon microspheres includes but is not limited to 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, and 2 μm. Similarly, the specific surface area of ​​the small-sized phenolic resin-based carbon microspheres includes but is not limited to 500 m 2 / g, 530m 2 / g, 550m 2 / g, 570m 2 / g, 580m 2 / g, 590m 2 / g、600m 2 / g, and the tap density of small-sized phenolic resin-based carbon microspheres includes but is not limited to 0.55g / cm 3 , 0.56g / cm 3 , 0.57g / cm 3 , 0.58g / cm 3 、0.59g / cm 3 , 0.6g / cm 3 .

[0037] It can be understood that in the present invention, by mixing the non-water-soluble thermosetting liquid phenolic resin and water, and adjusting the mass ratio of the non-water-soluble thermosetting liquid phenolic resin and water and the non-water-soluble thermosetting liquid phenolic resin and the dispersant, under this synergistic effect, the size and dispersibility of the microspheres can be better regulated, and the microspheres are cured under the combined influence of the acid catalyst, the curing agent and the thermal curing, and then carbonized to obtain small-sized phenolic resin-based carbon microspheres with small size and uniform particle size.

[0038] At the same time, an acid catalyst is added to the oil-in-water emulsion, and the catalytic effect of the acid catalyst is used to promote the solidification of the microspheres in the oil-in-water emulsion to form semi-solidified microspheres, thereby reducing the curing temperature and coordinating with the curing agent to further reduce the curing temperature. Therefore, in the curing reaction, no high-temperature or high-pressure equipment is required, and the curing time is short. Compared with the traditional preparation method, the equipment is simple, which achieves the effect of reducing energy consumption.

[0039] In addition, in the present invention, the raw materials are easily available and the cost is low, and the non-water-soluble thermosetting liquid phenolic resin is directly used, thereby avoiding the use of carcinogenic agents such as formaldehyde, and the method is safe and stable.

[0040] Therefore, the preparation method of the small-sized phenolic resin-based carbon microspheres of the present invention is safe and stable, the equipment is simple, and the cost is low. At the same time, the prepared small-sized phenolic resin-based carbon microspheres are small in size, uniform in particle size, and high in packing density, and can be well applied to the preparation of activated carbon, catalyst carriers, and electrode materials.

[0041] It should be noted that in the present invention, the microspheres formed by self-spheroidization of the non-water-soluble thermosetting liquid phenolic resin in water do not need to go through a process of first precipitation and nucleation followed by growth in the subsequent curing reaction, but rather a polymerization reaction occurs inside the existing phenolic resin microsphere phase, which can better control the particle size of the phenolic resin microspheres, thereby obtaining small-sized phenolic resin-based carbon microspheres with small and uniform particle sizes.

[0042] In step S1, the mass ratio of the water-insoluble thermosetting liquid phenolic resin to the curing agent is 2:1-10:1. Such a setting, on the one hand, can better improve the curing of the water-insoluble thermosetting liquid phenolic resin microspheres, and on the other hand, can synergize with the subsequent acidic catalyst to further reduce the curing temperature and reduce energy consumption.

[0043] Furthermore, the curing agent is selected from at least one of sodium bicarbonate, propylene carbonate, and vinyl acetate; the dispersant is selected from at least one of sodium dodecylbenzene sulfonate, dodecyltrimethylammonium chloride, and polyvinyl alcohol.

[0044] Optionally, in the step of mixing the water-insoluble thermosetting liquid phenolic resin, the curing agent, the dispersant and the water, the mixing temperature is 20° C.-50° C. and the mixing time is 5 min-30 min. Such an arrangement is conducive to forming a stable oil-in-water emulsion.

[0045] In step S2, in the step of adding an acid catalyst to the oil-in-water emulsion, an acidic emulsion is obtained, and the pH of the acidic emulsion is ≤ 0.25. Such a setting can better promote the curing of the microspheres, further reduce the curing temperature, and save energy consumption.

[0046] Furthermore, the mass ratio of the water-insoluble thermosetting liquid phenolic resin to the acidic catalyst is 1:1.2-1:1.6. Such a configuration can better control the pH value of the oil-in-water emulsion to be ≤ 0.25, and better reduce the curing temperature.

[0047] Furthermore, the acidic catalyst is selected from at least one of hydrochloric acid or nitric acid, preferably hydrochloric acid.

[0048] Optionally, in the step of adding the acid catalyst to the oil-in-water emulsion, the mixing time is 5 min to 20 min.

[0049] Optionally, the heat curing temperature is 80° C.-100° C., and the heat curing time is 0.5 h-5 h. With such an arrangement, the cured phenolic resin microspheres can be obtained better.

[0050] Optionally, after the heat curing, centrifugation, washing and drying are further performed to obtain phenolic resin microspheres, wherein the drying temperature is 60° C.-80° C. and the drying time is 10 h-24 h. Such an arrangement is conducive to obtaining phenolic resin microspheres with high purity and uniform particle size.

[0051] In one embodiment, the washing step comprises washing with deionized water for multiple times.

[0052] In one embodiment, an acid catalyst is added to the oil-in-water emulsion, and then the emulsion is placed in a water bath or an oil bath for thermal curing.

[0053] In step S3, the specific steps of carbonizing the phenolic resin microspheres are as follows: placing the phenolic resin microspheres in a tube furnace and carbonizing them under a protective atmosphere to obtain small-sized phenolic resin-based carbon microspheres.

[0054] Optionally, the protective atmosphere is selected from a nitrogen atmosphere and / or an inert gas atmosphere, and the inert gas atmosphere is preferably an argon atmosphere.

[0055] Optionally, the carbonization treatment temperature is 600°C-900°C, the heating rate is 1°C / min-10°C / min, and the carbonization treatment time is 0.5h-3h.

[0056] At the same time, the present invention also provides small-sized phenolic resin-based carbon microspheres prepared by the method for preparing small-sized phenolic resin-based carbon microspheres as described above.

[0057] Furthermore, the present invention also provides a use of the small-sized phenolic resin-based carbon microspheres as described above in activated carbon, catalyst carriers or supercapacitor electrode materials.

[0058] In one embodiment, the small-sized phenolic resin-based carbon microspheres prepared by the present invention are used as electrode materials and applied to supercapacitors, so that the supercapacitors have excellent specific capacity.

[0059] Below, the small-sized phenolic resin-based carbon microspheres and their preparation methods and applications will be further described by the following specific examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific conditions are specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.

[0060] Meanwhile, it should be noted that the specific surface area of ​​the phenolic resin-based carbon microspheres in the examples and comparative examples of the present invention is detected by a specific surface area analyzer, and the tap density of the phenolic resin-based carbon microspheres is detected by a tap density meter.

[0061] Example 1

[0062] 10g of non-water-soluble thermosetting liquid phenolic resin (CAS No. 9003-35-4), 2g of propylene carbonate, 7g of sodium dodecylbenzene sulfonate and 230g of deionized water were mixed, and stirred at room temperature for 10 minutes using a magnetic stirrer to obtain an oil-in-water emulsion; 14g of hydrochloric acid (mass concentration of 36%) was added to the oil-in-water emulsion, and stirring was continued for 10 minutes. After mixing evenly, it was placed in a water bath and stirred at 85°C for 2h to obtain a cured product, and then the cured product was centrifuged and washed with deionized water 3 times, and then dried at 60°C for 12h to obtain phenolic resin microspheres.

[0063] The phenolic resin microspheres obtained above were placed in a tubular furnace and carbonized under an argon atmosphere at a heating rate of 5°C / min, a carbonization temperature of 800°C, and a holding time of 1 h to obtain phenolic resin-based carbon microspheres.

[0064] The phenolic resin-based carbon microspheres prepared in this example were tested using a scanning electron microscope. The test results are as follows: Figure 1 As shown in the figure, it can be seen that the phenolic resin-based carbon microspheres are spherical, the average particle size of the phenolic resin-based carbon microspheres is 0.8 μm, and the particle size is uniform.

[0065] At the same time, the specific surface area of ​​the phenolic resin-based carbon microspheres of this embodiment is 545m 2 / g, tap density is 0.58g / cm 3 .

[0066] Example 2

[0067] 10g of non-water-soluble thermosetting liquid phenolic resin (CAS No. 9003-35-4), 5g of sodium bicarbonate, 10g of polyvinyl alcohol and 250g of deionized water were mixed, and stirred at room temperature for 30 minutes using a magnetic stirrer to obtain an oil-in-water emulsion; 16g of hydrochloric acid (mass concentration of 36%) was added to the oil-in-water emulsion, and stirring was continued for 20 minutes. After mixing evenly, it was placed in a water bath and stirred at 100°C for 0.5h to obtain a cured product, and then the cured product was centrifuged and washed with deionized water 3 times, and then dried at 80°C for 10h to obtain phenolic resin microspheres.

[0068] The phenolic resin microspheres obtained above were placed in a tube furnace and carbonized under an argon atmosphere at a heating rate of 8°C / min, a carbonization temperature of 700°C, and a holding time of 2h to obtain phenolic resin-based carbon microspheres, wherein the average particle size of the phenolic resin-based carbon microspheres was about 0.6 μm and the specific surface area was 580 m 2 / g, tap density is 0.60g / cm 3 .

[0069] Example 3

[0070] 10g of non-water-soluble thermosetting liquid phenolic resin (CAS No. 9003-35-4), 1g of propylene carbonate, 5g of sodium dodecylbenzene sulfonate and 210g of deionized water were mixed, and stirred at room temperature for 20 minutes using a magnetic stirrer to obtain an oil-in-water emulsion; 12g of hydrochloric acid (mass concentration of 36%) was added to the oil-in-water emulsion, and stirring was continued for 20 minutes. After mixing evenly, it was placed in a water bath and stirred at 90°C for 4 hours to obtain a cured product, and then the cured product was centrifuged and washed with deionized water 3 times, and then dried at 70°C for 20 hours to obtain phenolic resin microspheres.

[0071] The phenolic resin microspheres obtained above were placed in a tube furnace and carbonized under an argon atmosphere at a heating rate of 3°C / min, a carbonization temperature of 900°C, and a holding time of 0.5h to obtain phenolic resin-based carbon microspheres, wherein the average particle size of the phenolic resin-based carbon microspheres was about 1.8 μm, and the specific surface area was 510 m 2 / g, tap density is 0.57g / cm 3 .

[0072] Example 4

[0073] Example 4 is different from Example 1 only in that the mass of hydrochloric acid is 8 g, and the other conditions are the same, and phenolic resin-based carbon microspheres are obtained, wherein the average particle size of the phenolic resin-based carbon microspheres is about 2.0 μm, and the specific surface area is 500 m 2 / g, tap density is 0.56g / cm 3 .

[0074] Example 5

[0075] Example 5 is different from Example 1 in that nitric acid is used instead of hydrochloric acid and nitrogen atmosphere is used instead of argon atmosphere. The other conditions are the same to obtain phenolic resin-based carbon microspheres, wherein the average particle size of the phenolic resin-based carbon microspheres is about 1.2 μm and the specific surface area is 540 m 2 / g, tap density is 0.56g / cm 3 .

[0076] Comparative Example 1

[0077] Comparative Example 1 is different from Example 1 in that 3 g of sodium dodecylbenzene sulfonate is used, and the other conditions are the same to obtain phenolic resin-based carbon microspheres, wherein the average particle size of the phenolic resin-based carbon microspheres is about 5.0 μm and the specific surface area is 430 m 2 / g, tap density is 0.46g / cm 3 .

[0078] Comparative Example 2

[0079] Comparative Example 2 is different from Example 1 in that 150 g of deionized water is used, and the other conditions are the same to obtain phenolic resin-based carbon microspheres, wherein the average particle size of the phenolic resin-based carbon microspheres is about 5.0 μm and the specific surface area is 420 m 2 / g, tap density is 0.45g / cm 3 .

[0080] Comparative Example 3

[0081] Comparative Example 3 is different from Example 1 in that dimethyl silicone oil is used instead of deionized water, and the other conditions are the same to obtain phenolic resin-based carbon microspheres, wherein the average particle size of the phenolic resin-based carbon microspheres is about 4.0 μm, and the specific surface area is 460 m 2 / g, tap density is 0.49g / cm 3 .

[0082] Comparative Example 4

[0083] The only difference between Comparative Example 4 and Example 1 is that a water-soluble thermosetting phenolic resin is used instead of a water-insoluble thermosetting liquid phenolic resin, and other conditions are the same. No phenolic resin-based carbon microspheres can be obtained, and only phenolic resin-based carbon blocks can be obtained.

[0084] Comparative Example 5

[0085] Comparative Example 5 is different from Example 1 only in that the step of adding an acidic catalyst to the water-in-oil emulsion is omitted, that is, the water-in-oil emulsion is directly placed in a water bath and stirred for 6 hours at 85°C. The other conditions are the same to obtain phenolic resin-based carbon microspheres, wherein the average particle size of the phenolic resin-based carbon microspheres is about 2.5 μm and the specific surface area is 485 m 2 / g, tap density is 0.53g / cm 3 .

[0086] In this comparative example, since no acid catalyst was added, complete curing could not be achieved even after continuous stirring at 85° C. for 2 hours, and the stirring time had to be extended to 6 hours to achieve complete curing.

[0087] Comparative Example 6

[0088] Comparative Example 6 is different from Example 1 in that 10 g of non-water-soluble thermosetting liquid phenolic resin, 2 g of propylene carbonate, 7 g of sodium dodecylbenzene sulfonate, 14 g of hydrochloric acid (mass concentration of 36%) and 230 g of deionized water are mixed and stirred at room temperature for 20 min using a magnetic stirrer to obtain an oil-in-water emulsion; the oil-in-water emulsion is then placed in a water bath, and the other conditions are the same to obtain phenolic resin-based carbon microspheres, wherein the average particle size of the phenolic resin-based carbon microspheres is about 7.0 μm, and the specific surface area is 400 m 2 / g, tap density is 0.46g / cm 3 .

[0089] The phenolic resin-based carbon microspheres prepared in Examples 1-5 and Comparative Examples 1-6 were used as supercapacitor electrode materials and prepared into corresponding electrode sheets, and then the performance of the electrode sheets was tested. The test results are shown in Table 1 below.

[0090] Among them, the preparation method of the electrode sheet using the phenolic resin-based carbon microspheres of Examples 1-5 and Comparative Examples 1-3 and Comparative Examples 5-6 is as follows: First, weigh the phenolic resin-based carbon microspheres, acetylene black and PVDF in a mass ratio of 8:1:1 and place them in a 2mL round-bottom glass bottle. Then, add 1000μL of N-methylpyrrolidone and stir at room temperature for 6h. Finally, the prepared electrode slurry is evenly coated on the nickel foam sheet and vacuum dried at 80°C for 10h to obtain the electrode sheet to be tested.

[0091] The test method is as follows: the electrode sheet to be tested obtained above is used as the working electrode, a platinum electrode is used as the counter electrode, an Ag / AgCl electrode is used as the reference electrode, and a 6M potassium hydroxide solution is used as the electrolyte to perform a three-electrode constant current charge and discharge test.

[0092] Table 1

[0093]

[0094]

[0095] It can be seen from the data in Table 1 that compared with Example 1, in Example 4, due to the small amount of hydrochloric acid, the pH value in the water-in-oil emulsion is higher, the initial curing is incomplete, and the phenolic resin droplets that have not been initially cured collide with each other due to the intensified thermal motion in the subsequent heating and curing process to form larger droplets, resulting in an increase in the average particle size of the prepared phenolic resin-based carbon microspheres, resulting in a decrease in the specific capacity of the supercapacitor electrode material.

[0096] Compared with Example 1, in Comparative Example 1, due to the lower content of dispersant sodium dodecylbenzene sulfonate, the dispersion effect between the phenolic resin microspheres is affected, the collision probability between the microspheres is increased, resulting in a larger average particle size of the prepared phenolic resin-based carbon microspheres, and the specific capacity of the supercapacitor electrode material is lower.

[0097] Compared with Example 1, in Comparative Example 2, due to the lower content of deionized water, the self-spheroidization effect of the water-insoluble thermosetting liquid phenolic resin in water is affected, the collision probability between the microspheres is increased, and large-sized microspheres are easily formed, resulting in a larger average particle size of the prepared phenolic resin-based carbon microspheres, thereby lowering the specific capacity of the supercapacitor electrode material.

[0098] Compared with Example 1, in Comparative Example 3, since dimethyl silicone oil is used instead of deionized water, the water-insoluble thermosetting liquid phenolic resin is first dissolved in the dimethyl silicone oil and then precipitated, and is formed into spheres through the nucleation and growth process. The growth process is difficult to control and the particle size is large, resulting in a lower specific capacity of the supercapacitor electrode material.

[0099] Compared with Example 1, Comparative Example 4 uses a water-soluble thermosetting phenolic resin, which cannot self-spheroidize in water and will solidify as a whole during the heating process. It is impossible to form phenolic resin-based carbon microspheres, and only phenolic resin-based carbon blocks can be obtained. That is, the average particle size of the phenolic resin-based carbon microspheres in Comparative Example 4 does not exist, and since the particle size of the phenolic resin-based carbon block is too large, it cannot be used as an electrode material for a supercapacitor.

[0100] Compared with Example 1, in Comparative Example 5, since no acidic catalyst was added, the water-insoluble thermosetting liquid phenolic resin did not have a preliminary curing process at room temperature. In the subsequent heating and curing process, the phenolic resin droplets collided with each other due to the intensified thermal motion to form large droplets, which increased the average particle size, resulting in a larger average particle size of the phenolic resin-based carbon microspheres, resulting in a lower specific capacity of the supercapacitor electrode material.

[0101] Compared with Example 1, in Comparative Example 6, since hydrochloric acid is directly mixed with water-insoluble thermosetting liquid phenolic resin, propylene carbonate, sodium dodecylbenzene sulfonate and deionized water, the water-insoluble thermosetting liquid phenolic resin is initially solidified before the emulsion microspheres are formed, so that the particle size of the formed phenolic resin microspheres is larger, resulting in a larger average particle size of the phenolic resin-based carbon microspheres, resulting in a lower specific capacity of the supercapacitor electrode material.

[0102] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0103] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing small-sized phenolic resin-based carbon microspheres, characterized in that: The following steps are involved: Mixing a water-insoluble thermosetting liquid phenolic resin, a curing agent, a dispersant and water to obtain an oil-in-water emulsion, wherein the mass ratio of the water-insoluble thermosetting liquid phenolic resin to the water is 1:21-1:25, and the mass ratio of the water-insoluble thermosetting liquid phenolic resin to the dispersant is 1:1-2:1; adding an acidic catalyst to the oil-in-water emulsion, and then performing thermal curing to obtain phenolic resin microspheres; The phenolic resin microspheres are carbonized to obtain small-sized phenolic resin-based carbon microspheres, wherein the small-sized phenolic resin-based carbon microspheres have an average particle size of 0.5 μm-2 μm and a specific surface area of ​​500 m 2 / g-600m 2 / g, tap density is 0.55g / cm 3 -0.6g / cm 3 .

2. The method for preparing small-sized phenolic resin-based carbon microspheres according to claim 1, characterized in that: In the step of adding an acidic catalyst to the oil-in-water emulsion, an acidic emulsion is obtained, and the pH of the acidic emulsion is ≤0.

25.

3. The method for preparing small-sized phenolic resin-based carbon microspheres according to claim 1, characterized in that: The mass ratio of the non-water-soluble thermosetting liquid phenolic resin to the curing agent is 2:1-10:1; And / or, the mass ratio of the water-insoluble thermosetting liquid phenolic resin to the acidic catalyst is 1:1.2-1:1.

6.

4. The method for preparing small-sized phenolic resin-based carbon microspheres according to claim 1, characterized in that: The curing agent is selected from at least one of sodium bicarbonate, propylene carbonate and vinyl acetate; And / or, the dispersant is selected from at least one of sodium dodecylbenzene sulfonate, dodecyltrimethylammonium chloride and polyvinyl alcohol; And / or, the acidic catalyst is selected from at least one of hydrochloric acid and nitric acid.

5. The method for preparing small-sized phenolic resin-based carbon microspheres according to claim 1, characterized in that: In the step of mixing the non-water-soluble thermosetting liquid phenolic resin, the curing agent, the dispersant and water, the mixing temperature is 20° C.-50° C. and the mixing time is 5 min-30 min; And / or, in the step of adding the acidic catalyst to the oil-in-water emulsion, the mixing time is 5 min to 20 min.

6. The method for preparing small-sized phenolic resin-based carbon microspheres according to claim 1, characterized in that: The thermal curing temperature is 80°C-100°C, and the thermal curing time is 0.5h-5h.

7. The method for preparing small-sized phenolic resin-based carbon microspheres according to claim 1, characterized in that: After the thermal curing, the process further includes centrifugation, washing and drying to obtain phenolic resin microspheres, wherein the drying temperature is 60° C.-80° C. and the drying time is 10 h-24 h.

8. The method for preparing small-sized phenolic resin-based carbon microspheres according to claim 1, characterized in that: In the step of carbonizing the phenolic resin microspheres, the protective atmosphere is selected from nitrogen atmosphere and / or inert gas atmosphere, the carbonization temperature is 600°C-900°C, the heating rate is 1°C / min-10°C / min, and the carbonization time is 0.5h-3h.

9. Small-sized phenolic resin-based carbon microspheres prepared by the method for preparing small-sized phenolic resin-based carbon microspheres according to any one of claims 1 to 8.

10. Use of the small-sized phenolic resin-based carbon microspheres as claimed in claim 9 in activated carbon, catalyst carrier or supercapacitor electrode material.

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