TW202124276A - Manufacturing method of composite fiber with high specific capacity mixing and electrostatic spinning polyacrylonitrile, polyacrylonitrile grafted graphene oxide polymer and polyvinylpyrrolidone - Google Patents

Abstract

This invention discloses a manufacturing method of a composite fiber with high specific capacity. The manufacturing method includes: mixing polyacrylonitrile, a polyacrylonitrile grafted graphene oxide polymer and polyvinylpyrrolidone, and performing electrostatic spinning; then, washing away the polyvinylpyrrolidone to increase pores; and then, forming a carbonized composite fiber at high temperature. In addition, this invention further discloses another method including: mixing polyacrylonitrile, benzoxazine and polyvinylpyrrolidone, and performing electrostatic spinning; and then, washing away the polyvinylpyrrolidone, and performing high-temperature carbonization to obtain a open-loop structure of the benzoxazine. Therefore, the phenomenon of thermal contraction may be effectively reduced, pores may be increased, and furthermore, an electrode material with excellent capacitive performances is provided.

Description

Manufacturing method of composite fiber with high specific capacitance

The invention relates to the technical field of fibers, in particular to a method for manufacturing composite fibers with high specific capacitance.

Press, for example, China Publication No. CN108589025A invention patent case "Method for preparing graphene-carbon composite nanofibers", which uses graphene and polyacrylonitrile (hereinafter referred to as PAN) as raw materials, and then electrospinning method To prepare graphene-carbon composite nanofibers to provide electrode materials with good capacitance performance. However, with the demand for energy derived from modern and increasingly advanced technology, conventional electrode materials have been unable to meet the requirements of today's capacitors for electrodes, and there is a problem of too low electric power output. Accordingly, how to effectively improve the capacitance performance of the conventional electrode materials will be the area where the relevant industry still needs to work hard.

The main purpose of the present invention is to provide a method for manufacturing a composite fiber with a high specific capacitance, which can prepare a carbonized composite fiber with a high specific surface area and a high capacitance, thereby providing an electrode material with excellent capacitance performance.

In order to achieve the above-mentioned object, the present invention discloses a method for manufacturing a composite fiber with high specific capacitance. After mixing polyacrylonitrile and polyacrylonitrile grafted graphene oxide polymer with polyvinylpyrrolidone and performing electrospinning, The polyvinylpyrrolidone is removed to increase the pores, and then undergoes high temperature to form a carbonized composite fiber.

Wherein, the specific capacitance value of the carbonized composite fiber is at least 90 F/g.

Wherein, an activation process is performed on the carbonized composite fiber to obtain an activated carbon composite fiber, and the specific capacitance value of the activated carbon composite fiber is at least 170 F/g.

Furthermore, the present invention also discloses a method for manufacturing a composite fiber with high specific capacitance. After mixing polyacrylonitrile, benzoxazine and polyvinylpyrrolidone and performing electrospinning, the polyvinylpyrrolidone is removed to increase the porosity. , And then form a carbonized composite fiber after high temperature.

Wherein, the specific capacitance value of the carbonized composite fiber is at least 40 F/g. Wherein, an activation process is performed on the carbonized composite fiber to obtain an activated carbon composite fiber, and the specific capacitance value of the activated carbon composite fiber is at least 290 F/g.

In addition, the present invention further discloses a method for manufacturing a composite fiber with a high specific capacitance, which includes the following steps: Step A: After the graphene oxide, acrylonitrile and the initiator are mixed, the reaction is heated to generate polyacrylonitrile grafted graphene oxide polymer; Step B: Add polyacrylonitrile for electrospinning; Step D: The carbonized composite fiber is formed through high temperature.

Wherein, the initiator is selected from any one of the group consisting of azobisisobutyronitrile, azobisisovaleronitrile, azobisisocapronitrile, and azobisisoheptonitrile.

Among them, in step A, first disperse the graphene oxide in dimethylformamide, then add acrylonitrile and initiator, and heat and stir in an oil bath for two days. Methylformamide is washed, and finally filtered and dried to obtain polyacrylonitrile grafted graphene oxide polymer.

Wherein, the specific capacitance value of the carbonized composite fiber is at least 90 F/g.

Wherein, in step B, the polyacrylonitrile grafted graphene oxide polymer is first added to dimethylformamide, and after ultrasonic vibration for 6 hours, polyacrylonitrile and polyvinylpyrrolidone are added, and the temperature is at room temperature. Stir for 6 hours until the polyacrylonitrile and polyvinylpyrrolidone are completely dissolved.

Wherein, step C is further included between step B and step D. After electrospinning, the polyvinylpyrrolidone is removed by a cleaning procedure to increase the porosity.

The steps of the cleaning procedure are as follows: Step I: Soak the fiber obtained by electrospinning in a mixed solution of deionized water and ethanol, and stir for 4 hours; Step II: Next, change the mixed solution and raise the temperature to 80 °C, and stir for 12 hours; Step III: After replacing the mixed solution again, add 8000 ppm of sodium hypochlorite, stir for 50 minutes, and vibrate with ultrasound for 3 minutes; Step IV: Replace the mixed solution and wash off excess sodium hypochlorite; Step V: After extraction and washing for 12 hours, stirring at 90 °C for 12 hours; Step VI: Drying at 60 °C for 6 hours; Step VII: Finally, dry at 120°C in a vacuum environment.

Among them, in step D, the first stage of heat treatment is performed at a temperature of 1 C/min to 160 C~320 C under an oxygen environment, and after holding the temperature for 2 hours, the second stage is performed in a nitrogen environment. The stage heat treatment is to raise the temperature at 5 C/min to 900 C, and then lower the temperature after holding the temperature for 1 hour to form a carbonized composite fiber, and the specific capacitance value of the activated carbon composite fiber is at least 170 F/g.

In addition, the present invention also discloses a method for manufacturing a composite fiber with a high specific capacitance, which includes the following steps: Step A: mixing acrylonitrile, polyvinylpyrrolidone and benzoxazine and electrospinning; Step C: The carbonized composite fiber is formed through high temperature, and an oxygen-containing oxazine ring is formed at the same time, so that the fibers will not adhere to each other in a high temperature environment and achieve the effect of fixing the fiber structure.

Wherein, the specific capacitance value of the carbonized composite fiber is at least 40 F/g.

Wherein, step B is further included between step A and step C. After electrospinning, the polyvinylpyrrolidone is removed by a cleaning procedure to increase the porosity.

The steps of the cleaning procedure are as follows: Step I: Soak the fiber obtained by electrospinning in a mixed solution of deionized water and ethanol, and stir for 4 hours; Step II: Next, change the mixed solution and raise the temperature to 80 °C, and stir for 12 hours; Step III: After replacing the mixed solution again, add 8000 ppm of sodium hypochlorite, stir for 50 minutes, and vibrate with ultrasound for 3 minutes; Step IV: Replace the mixed solution and wash off excess sodium hypochlorite; Step V: After extraction and washing for 12 hours, stirring at 90 °C for 12 hours; Step VI: Drying at 60 °C for 6 hours; Step VII: Finally, dry at 120°C in a vacuum environment.

Among them, in step C, the first stage heat treatment is carried out under the ambient conditions of oxygen, and the temperature is raised at 1 C/min to the range of 160 C~320 C and the temperature is held for 2 hours; then, it is carried out in a nitrogen environment The second stage of heat treatment is to raise the temperature at 5 C/min to 900 C, and then lower the temperature after holding the temperature for 1 hour to form a carbonized composite fiber, and the specific capacitance value of the activated carbon composite fiber is at least 290 F/g.

Hereinafter, a few examples will be given to illustrate the method of manufacturing the composite fiber with high specific capacitance disclosed in the present invention, so as to prepare a carbonized composite fiber with high specific surface area and high capacitance, so as to achieve the purpose of providing electrode materials with excellent capacitance performance, and Please refer to the flowchart shown in Figure 1.

Example 1: Preparation of CNF-UF/GNS-g carbonized composite fiber

First, disperse graphite and sulfuric acid in a ratio of 1 g:50 ml, then add potassium permanganate, heat and stir in an oil bath at 60°C for one day, then add deionized water, then add hydrogen peroxide, and wait for it to settle After being filtered, then washed with deionized water, and finally freeze-dried to obtain Graphite Oxide (hereinafter referred to as GO) powder.

Next, first disperse GO and dimethylformamide (hereinafter referred to as DMF) at a ratio of 0.1g:80ml, then add acrylonitrile (AN) monomer and initiator, and heat in an oil bath at 60°C After stirring for two days, it was precipitated with methanol and then filtered, then washed with DMF, and finally filtered and dried to obtain polyacrylonitrile grafted graphene oxide polymer (hereinafter referred to as GO-g-PAN).

Then, calculate and prepare 8wt% PAN-DMF solution by weight percentage, and oscillate with ultrasonic for 6 hours. Then, add an appropriate amount of PAN and polyvidone (Polyvidone, hereinafter referred to as PVP), and stir at room temperature for 6 hours until the PAN and polyvinylpyrrolidone are completely dissolved.

Then, put the configured PAN/ PVP/ GO-g-PAN/ DMF solution into the injection syringe, install the needle in the syringe, and use the syringe pump to transfer the PAN/ PVP/ GO-g-PAN/ DMF The solution is delivered to the needle, the working distance is 14 cm, voltage is applied, and the process changes are observed.

And after electrospinning, the PVP is removed by a cleaning process to increase the pores, so that composite nanofibers, namely PAN/GO-g-PAN 99/1, can be prepared.

Among them, the steps of the cleaning procedure are as follows: Step I: Soak the fiber obtained by electrospinning in a mixed solution of deionized water and ethanol, and stir for 4 hours; Step II: Next, change the mixed solution and raise the temperature to 80 °C, and stir for 12 hours; Step III: After replacing the mixed solution again, add 8000 ppm of sodium hypochlorite, stir for 50 minutes, and vibrate with ultrasound for 3 minutes; Step IV: Replace the mixed solution and wash off excess sodium hypochlorite; Step V: After extraction and washing for 12 hours, stirring at 90 °C for 12 hours; Step VI: Drying at 60 °C for 6 hours; Step VII: Next, continue drying at 120°C in a vacuum environment.

Finally, the composite nanofibers are placed in a tubular high-temperature furnace to form carbonized composite fibers through high temperature. In other words, during the carbonization process, PAN will be heated to produce reactions such as cyclization, dehydrogenation and oxygen attack, and form a ladder structure (Ladder Polymer), thereby making the structure of the carbonized composite fiber more stable. In this embodiment, the implementation steps of the carbonization process are as follows. First, under an oxygen environment, the temperature is raised to 260 C~320 C at 1 C/min to perform the first stage heat treatment, and the temperature is maintained for 2 hours. Then, the second stage heat treatment is carried out in a nitrogen environment, which is raised to 900 C at a rate of 5 C/min. After holding the temperature for 1 hour, the temperature is lowered to form a carbonized composite fiber, namely CNF-UF/GNS-g99/1.

In order to explore the influence of GO-g-PAN on the capacitance performance of the fiber, the corresponding control group was tested according to the above steps. Compared with replacing GO-g-PAN with unmodified GO, after electrospinning and carbonization Obtain different ratios of carbonized composite fibers, namely CNF-UF, CNF-UF/GNS 99/1.

Accordingly, with the analysis results shown in Table 1, the specific capacitance of CNF-UF/GNS-g is at least 90 F/g, which is higher than that of CNF-UF and higher than that of CNF-UF/GNS. The specific capacitance can prove that the performance of the capacitor is significantly improved. Therefore, the products produced by this method should be widely used. Table 1. Capacitance analysis test of experimental group and control group CV specific capacitance (F/g) Constant current charge and discharge specific capacitance (F/g) test group CNF-UF/GNS-g99/1 104.4 93.1 Control group CNF-UF 31.0 23.0 CNF-UF/GNS99/1 69.2 49.0

In addition, the diameters of the carbonized composite fibers CNF-UF, CNF-UF/GNS 99/1, and CNF-UF/GNS-g 99/1 are 74.0±12 nm, 89.0±16 nm, and 92.0±14 nm, respectively.

Example 2: Preparation of activated carbon composite fiber

In this embodiment, the steps of preparing the fiber are similar to Example 1, and the main difference is that the carbonized composite fiber is further subjected to an activation process to increase its porosity, thereby preparing an activated carbon composite fiber, namely ACNF-UF, ACNF -UF/GNS99/1. In detail, because the carbonization process cannot avoid the formation of hydrocarbon tar, it is easy to adhere and block in the pores of the carbonized composite fiber, reducing its surface area. Therefore, the activation process must be used to remove the tar and promote the pores on the fiber surface. The formation of structures to increase the surface area. As shown in Table 2, the specific capacitance value of the activated carbon composite fiber is at least 170 F/g, which is obviously improved. Table 2. Capacitance analysis test of activated carbon composite fiber CV specific capacitance (F/g) Constant current charge and discharge specific capacitance (F/g) ACNF-UF 93.5 66.4 ACNF-UF/GNS99/1 208.4 167.5 ACNF-UF/GNS-g99/1 188.0 179.2

Example 3: Preparation of CNF-UF/BZ carbonized composite fiber

In this embodiment, the second composition is changed from GO-g-PAN to Benzoxazine (hereinafter referred to as BZ), and the weight ratio between PAN and BZ is between 100:0 and 50 :50, and then prepare nano composite fibers of different proportions, namely CNF-UF and CNF-UF/BZ. The part that needs special attention is: before electrospinning, in the step of preparing PAN/PVP/BZ/DMF solution, you need to make sure that the polymer is completely dissolved before adding BZ to the solution, and wait 12 hours for the BZ to completely dissolve , Only started electrospinning. In addition, the carbonization step of this embodiment is similar to Example 1, the main difference is that the first stage heat treatment is carried out under the ambient conditions of oxygen, and the temperature is raised at 1 C/min to the range of 160 C~320 C; then, the temperature is maintained in the nitrogen The second stage of heat treatment is carried out in the environment of, the temperature is raised to 900 C at 5 C/min, and the temperature is lowered after holding the temperature for 1 hour to form a carbonized composite fiber.

（1）

（2）In particular, during the carbonization process, because BZ will react into an oxygen-containing oxazine ring early, the PAN-UF nanofibers will not adhere to each other in a high temperature environment, and effectively reduce the thermal shrinkage phenomenon to achieve fixation. The utility of the ultrafine nanofiber structure increases its specific capacitance. Among them, the BZ ring-opening reaction formula is as shown in the following formula (1), and PAN-UF/BZ will form an interpenetrating network structure (IPN, Interpenetreting network) after being oxidized as shown in the following formula (2).

(1)

(2)

（3）In addition, the steps of preparing the BZ monomer: first, pour bisphenol A, aniline and formaldehyde into a flask according to a weight ratio of 1:2:4, and then place the flask in an oil pan at 100~110°C with heating and stirring 4 hours. Then, after cooling down, pour the solution in the flask into chloroform, and then add it dropwise to the sodium hydroxide aqueous solution. At this time, the solution will be stratified, so take out the upper liquid to reduce Concentrate and extract chloroform. Finally, put it into a vacuum oven to dry, and take out the grinding powder to obtain BZ powder. Among them, the BZ synthesis reaction formula is the following formula (3).

(3)

Accordingly, with the analysis results shown in Table 3, the specific capacitance of CNF-UF/BZ is at least 40 F/g, which is obviously higher than that of CNF-UF, so adding BZ will effectively increase the specific capacitance. Table 3. Capacitance analysis test of CNF-UF/BZ composite fiber CV specific capacitance (F/g) Constant current charge and discharge specific capacitance (F/g) CNF-UF 31.0 23.0 CNF-UF/BZ 74.0 44.5

Among them, the diameter of the carbonized composite fiber CNF-UF/BZ is 60.4±13 nm.

In addition, in this embodiment, the carbonized composite fiber is further subjected to an activation procedure, and the implementation is the same as the activation procedure steps of Example 2, so as to prepare activated carbon composite fibers, namely ACNF-UF and ACNF-UF/BZ. As shown in Table 4, the specific capacitance of ACNF-UF/BZ is at least 290 F/g, and its specific capacitance is significantly improved. Table 4. Capacitance analysis test of CNF-UF/BZ activated carbon composite fiber CV specific capacitance (F/g) Constant current charge and discharge specific capacitance (F/g) ACNF-UF 93.5 66.4 ACNF-UF/BZ 301.0 295.3

The above is only to illustrate the present invention in detail with the examples. Those who are familiar with the technical field, without departing from the spirit of the present invention, make any simple modifications or changes to the embodiments in the specification shall be within the scope of the patent application for this application. Incoming contenders.

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Fig. 1 is a schematic flow chart of the manufacturing method of the composite fiber with high specific capacitance according to the present invention.

Claims (19)

A method for manufacturing composite fiber with high specific capacitance is to mix polyacrylonitrile and polyacrylonitrile grafted graphene oxide polymer with polyvinylpyrrolidone and perform electrospinning, and then remove the polyvinylpyrrolidone to increase the pores. Then, after high temperature, a carbonized composite fiber is formed. The method for manufacturing a composite fiber with a high specific capacitance according to claim 1, wherein the specific capacitance value of the carbonized composite fiber is at least 90 F/g. The method for manufacturing a composite fiber with a high specific capacitance according to claim 1, wherein an activation process is performed on the carbonized composite fiber to obtain an activated carbon composite fiber, and the specific capacitance value of the activated carbon composite fiber is at least 170 F /g. A method for manufacturing composite fiber with high specific capacitance. After mixing polyacrylonitrile, benzoxazine and polyvinylpyrrolidone and performing electrospinning, the polyvinylpyrrolidone is removed to increase the pores, and then carbonized at high temperature. Composite fiber. The method for manufacturing a composite fiber with a high specific capacitance according to claim 4, wherein the specific capacitance value of the carbonized composite fiber is at least 40 F/g. The method for manufacturing a composite fiber with a high specific capacitance according to claim 4, wherein an activation process is performed on the carbonized composite fiber to obtain an activated carbon composite fiber, and the specific capacitance value of the activated carbon composite fiber is at least 290 F /g. A method for manufacturing composite fiber with high specific capacitance includes the following steps: Step A: After the graphene oxide, acrylonitrile and the initiator are mixed, the reaction is heated to generate polyacrylonitrile grafted graphene oxide polymer; Step B: Add polyacrylonitrile and polyvinylpyrrolidone for electrospinning; Step D: Form a carbonized composite fiber through high temperature. The method for manufacturing a composite fiber of high specific capacitance according to claim 7, wherein the initiator is selected from the group consisting of azobisisobutyronitrile, azobisisovaleronitrile, azobisisocapronitrile and azobisisoheptonitrile Any one of the formed group. The method for manufacturing a composite fiber with a high specific capacitance according to claim 7, wherein, in step A, the graphene oxide is first dispersed in dimethylformamide, then acrylonitrile and initiator are added, and the mixture is placed in an oil bath After heating and stirring for two days, it was precipitated with methanol and then filtered, then washed with dimethylformamide, and finally filtered and dried to obtain polyacrylonitrile grafted graphene oxide polymer. The method for manufacturing a composite fiber with a high specific capacitance according to claim 7, wherein the specific capacitance value of the carbonized composite fiber is at least 90 F/g. As described in claim 7, the method for manufacturing a composite fiber with a high specific capacitance further includes step C. After electrospinning, the polyvinylpyrrolidone is removed by a cleaning process to increase the porosity. The method for manufacturing a composite fiber with a high specific capacitance according to claim 11, wherein the steps of the cleaning procedure are as follows: Step I: Soak the fiber obtained by electrospinning in a mixed solution of deionized water and ethanol, and stir for 4 hours; Step II: Next, change the mixed solution and raise the temperature to 80 °C, and stir for 12 hours; Step III: After replacing the mixed solution again, add 8000 ppm of sodium hypochlorite, stir for 50 minutes, and vibrate with ultrasound for 3 minutes; Step IV: Replace the mixed solution and wash off excess sodium hypochlorite; Step V: After extraction and washing for 12 hours, stirring at 90 °C for 12 hours; Step VI: Drying at 60 °C for 6 hours; Step VII: Finally, dry at 120°C in a vacuum environment. The method for manufacturing a composite fiber with a high specific capacitance according to claim 7, wherein, in step B, the polyacrylonitrile grafted graphene oxide polymer is first added to dimethylformamide, and ultrasonic vibration is performed 6 After hours, add polyacrylonitrile and polyvinylpyrrolidone, and stir at room temperature for 6 hours until the polyacrylonitrile and polyvinylpyrrolidone are completely dissolved. The method for manufacturing a composite fiber with a high specific capacitance according to claim 7, wherein, in step D, the temperature is raised to 260C~320C at a rate of 1 C/min under an oxygen environment to perform the first stage heat treatment, and After holding the temperature for 2 hours, perform the second-stage heat treatment in a nitrogen environment. The temperature is raised at 5 C/min to 900 C. After holding the temperature for 1 hour, the temperature is lowered to form a carbonized composite fiber. The ratio of the activated carbon composite fiber is The capacitance value is at least 170 F/g. A method for manufacturing composite fiber with high specific capacitance includes the following steps: Step A: Mix acrylonitrile, polyvinylpyrrolidone and benzoxazine and perform electrospinning; Step C: The carbonized composite fiber is formed through high temperature, and an oxygen-containing oxazine ring is formed at the same time. The method for manufacturing a composite fiber with a high specific capacitance according to claim 15, wherein the specific capacitance value of the carbonized composite fiber is at least 40 F/g. The method for manufacturing a composite fiber with a high specific capacitance as described in claim 15 further includes step B, after electrospinning, the polyvinylpyrrolidone is removed by a scrubbing process to increase porosity. The method for manufacturing a composite fiber with a high specific capacitance according to claim 17, wherein the steps of the cleaning procedure are as follows: Step I: Soak the fiber obtained by electrospinning in a mixed solution of deionized water and ethanol, and stir for 4 hours; Step II: Next, after replacing the mixed solution, the temperature is raised to 80°C and stirred for 12 hours; Step III: After replacing the mixed solution again, add 8000 ppm of sodium hypochlorite, stir for 50 minutes, and vibrate with ultrasound for 3 minutes; Step IV: Replace the mixed solution and wash off excess sodium hypochlorite; Step V: After extraction and washing for 12 hours, stirring at 90°C for 12 hours; Step VI: Drying at 60°C for 6 hours; Step VII: Finally, dry at 120°C in a vacuum environment. The method for manufacturing a composite fiber with a high specific capacitance according to claim 15, wherein, in step C, the first stage heat treatment is carried out under an oxygen environment, and the temperature is raised to a temperature range of 160C~320C at 1 C/min. Temperature; Next, the second stage heat treatment is carried out in a nitrogen environment, the temperature is raised to 900 C at 5 C/min, and then the temperature is lowered to form a carbonized composite fiber, and the specific capacitance value of the activated carbon composite fiber is at least 290 F/g .

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