Preparation method of ultrafine PEDOT:PSS conductive fiber and micro-supercapacitor made therefrom

Abstract

The present invention relates to a preparation method of ultrafine PEDOT:PSS conductive fibers and a micro-supercapacitor made therefrom in the technical field of the preparation of organic polymer conductive fibers. Specifically, the prepared PEDOT:PSS spinning solution enters a mixed coagulation bath composed of N,N-dimethylacetamide and water through a wet spinning spinneret for solidification molding. 0.01-0.16 mol / L of methanesulfonic acid is added to the mixed coagulation bath of N,N-dimethylacetamide and water. After the solidified fiber is dried and cooled, ultrafine PEDOT:PSS conductive fibers for micro-supercapacitors are obtained. The preparation method of the present invention simply and efficiently prepares continuous ultrafine PEDOT:PSS conductive fibers for micro-supercapacitors. The ultrafine diameter significantly improves the conductivity and electrochemical activity of the PEDOT:PSS conductive fibers, providing excellent electrode materials for the preparation of fiber-based supercapacitor arrays. The present invention first realizes the application of PEDOT:PSS conductive fibers in the field of micro-supercapacitors, expanding the application field of PEDOT:PSS conductive fibers.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of organic polymer conductive fibers, and particularly relates to a preparation method of ultrafine PEDOT:PSS conductive fibers and a micro-supercapacitor made therefrom. Background Art

[0002] Poly(3,4-ethylenedioxythiophene) (PEDOT) has great application potential in the field of energy storage and conversion due to its excellent conductivity and energy storage performance. The rigid main-chain structure makes PEDOT insoluble in common organic solvents, and it is difficult to directly prepare continuous PEDOT fibers. After PEDOT is doped with poly(styrenesulfonate) anions (PSS), a uniformly dispersed and stable PEDOT:PSS aqueous dispersion can be obtained, and continuous PEDOT:PSS fibers can be rapidly prepared by wet spinning technology, which has broad application prospects in fiber-based energy storage devices. However, so far, there is still a large room for improvement in the conductivity and energy storage performance of PEDOT:PSS fibers. First, the addition of insulating PSS reduces the conductivity and energy storage performance of PEDOT:PSS fibers. Therefore, how to remove the insulating PSS in PEDOT:PSS fibers has become an important way to improve the conductivity and energy storage performance of PEDOT:PSS conductive fibers. Second, increasing the specific surface area of the fibers is another important strategy to improve the energy storage performance of fiber electrodes. Therefore, how to simply and efficiently prepare PEDOT:PSS conductive fibers with less PSS content and large specific surface area has become an important research topic in the field of fiber-based energy storage devices.

[0003] In previous studies, people usually soaked the formed PEDOT:PSS fibers in solvents such as ethylene glycol, dimethyl sulfoxide or sulfuric acid to remove PSS. However, these secondary treatment processes are likely to cause irreversible damage to the properties of the fibers. And the methods for increasing the specific surface area of PEDOT:PSS conductive fibers mainly focus on constructing more complex microstructures on the fiber surface. Although these methods can effectively achieve the purpose of reducing the PSS content or increasing the specific surface area of the fibers, they are usually cumbersome to operate, have poor durability and greatly increase the process cost. Summary of the Invention

[0004] Aiming at the problems of cumbersome operation and high cost in the prior art for preparing high-performance PEDOT:PSS conductive fibers, the present invention provides an ultrafine PEDOT:PSS conductive fiber for a micro-supercapacitor and a preparation method thereof. By adjusting the components of the coagulation bath in the wet spinning during fiber preparation, the insulating PSS is removed while the fiber diameter is refined, and the orientation arrangement of PEDOT is promoted, which improves the electrochemical active area of the fiber while also improving the conductivity and energy storage performance of the fiber.

[0005] The object of the present invention is achieved as follows. A preparation method of ultrafine PEDOT: PSS conductive fibers and a micro-supercapacitor made therefrom, characterized by comprising the following steps:

[0006] The first step: preparing a PEDOT: PSS spinning solution;

[0007] The second step: using an injection pump to uniformly pump the spinning solution into a mixed coagulation bath containing N, N-dimethylacetamide (DMAc) and water through a wet spinning spinneret for solidification molding. Methanesulfonic acid (MSA) is added to the mixed coagulation bath of DMAc and water in a proportion of 0.01 - 0.16 mol / L; after the solidified and formed fibers are fished out, they are dried, cooled and collected to obtain ultrafine PEDOT: PSS conductive fibers for micro-supercapacitors.

[0008] In the preparation of the ultrafine PEDOT: PSS conductive fibers of the present invention, with DMAc and water as the main body, and the sulfonic acid-based small molecule MSA is added as an auxiliary to the coagulation bath for wet spinning, continuous ultrafine PEDOT: PSS conductive fibers with a low PSS content are simply and efficiently prepared. Among them, MSA is used to replace the sulfonic acid group of PSS to dissociate PSS from the PEDOT molecular chain; DMAc, as a polar solvent, can promote the diffusion of PSS into the coagulation bath and cause the orientation arrangement of the PEDOT molecular chain; the presence of water ensures that the spinning solution does not solidify too quickly, allowing enough time for the PSS in the spinning solution jet to be removed and refined, thereby reducing the content of insulating PSS components in the fibers and improving the conductivity of the fibers. Therefore, the PEDOT: PSS fibers prepared by the spinning process of the present invention have an ultrafine diameter, high conductivity and excellent energy storage performance, and can be better applied to flexible energy storage devices.

[0009] Further, in the first step, the PEDOT: PSS spinning solution is prepared by ultrasonically vibrating a PEDOT: PSS aqueous dispersion with an ultrasonic oscillator for 15 minutes at room temperature, mixing evenly and then standing for defoaming to obtain a uniform spinning solution.

[0010] The concentration of the PEDOT: PSS aqueous dispersion is 1 - 13 mg / mL.

[0011] Further, in the second step, the propulsion speed of the injection pump is 0.5 - 5 ml / h.

[0012] Still further, in the second step, in the mixed coagulation bath, the volume ratio of DMAc to water is 10:1, and MSA is added in a proportion of 0.01 - 0.16 mol / L based on the mixed coagulation bath of DMAc and water.

[0013] To control the fiber diameter, in the second step, the pore diameter of the spinneret is 0.06 - 0.26 mm.

[0014] The present invention also provides a micro-supercapacitor prepared with the above-mentioned ultrafine PEDOT:PSS conductive fibers. The fiber-based micro-supercapacitors (FMSCs) of the present invention have good performance. The micro-supercapacitor array assembled with the capacitors has a small volume. Approximately 150 micro-supercapacitors can be integrated on an area of 4.5 cm 2 and generate a high voltage of 135 V. Description of the Drawings

[0015] Figure 1 SEM image of the wet-spun fiber of 1 mg / ml PEDOT:PSS spinning solution in a mixed coagulation bath of DMAc and water containing 0.16 mol / L MSA, the pore diameter of the spinneret is 0.06 mm, and the injection pump propulsion speed is 2 ml / h;

[0016] Figure 2 SEM image of the wet-spun fiber of 13 mg / ml PEDOT:PSS spinning solution in a mixed coagulation bath of DMAc and water containing 0.01 mol / L MSA, the pore diameter of the spinneret is 0.26 mm, and the injection pump propulsion speed is 5 ml / h;

[0017] Figure 3 SEM image of the wet-spun fiber of 6 mg / ml PEDOT:PSS spinning solution in a mixed coagulation bath of DMAc and water containing 0.16 mol / L MSA, the pore diameter of the spinneret is 0.06 mm, and the injection pump propulsion speed is 0.5 ml / h;

[0018] Figure 4 SEM image of the wet-spun fiber of 13 mg / ml PEDOT:PSS spinning solution in a mixed coagulation bath of DMAc and water containing 0.16 mol / L MSA, the pore diameter of the spinneret is 0.26 mm, and the injection pump propulsion speed is 5 ml / h;

[0019] Figure 5 SEM image of the wet-spun fiber of 13 mg / ml PEDOT:PSS spinning solution in a mixed coagulation bath of DMAc and water containing 0.30 mol / L MSA, the pore diameter of the spinneret is 0.26 mm, and the injection pump propulsion speed is 5 ml / h;

[0020] Figure 6SEM image of the wet-spun fiber of 25 mg / ml PEDOT: PSS spinning solution in a mixed coagulation bath of DMAc and water with 0.16 mol / L MSA added. The pore diameter of the spinneret is 0.26 mm, and the propulsion speed of the syringe pump is 5 ml / h;

[0021] Figure 7 SEM image of the wet-spun fiber of 13 mg / ml PEDOT: PSS spinning solution in a mixed coagulation bath of DMAc and water with 0.16 mol / L MSA added. The pore diameter of the spinneret is 0.34 mm, and the propulsion speed of the syringe pump is 5 ml / h;

[0022] Figure 8 SEM image of the wet-spun fiber of 13 mg / ml PEDOT: PSS spinning solution in a mixed coagulation bath of DMAc and water with 0.16 mol / L MSA added. The pore diameter of the spinneret is 0.26 mm, and the propulsion speed of the syringe pump is 10 ml / h;

[0023] Figure 9 SEM image of the wet-spun fiber of 13 mg / ml PEDOT: PSS spinning solution in a mixed coagulation bath of DMAc and water with 0.02 mol / L FeCl3 added. The pore diameter of the spinneret is 0.26 mm, and the propulsion speed of the syringe pump is 5 ml / h;

[0024] Figure 10 Schematic diagrams of a micro-supercapacitor fabricated by assembling ultrafine PEDOT: PSS conductive fibers, its array, and output voltage detection. Embodiment

[0025] The spinning method of the present invention is simulated by examples below for a detailed description of the present invention. It is necessary to point out here that the following examples are only for further illustration of the present invention and should not be construed as limiting the protection scope of the present invention. It can be understood that after reading the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims of the present invention. Example 1

[0026] First, prepare the PEDOT: PSS spinning solution: By adding water for dilution, dilute the PEDOT: PSS aqueous dispersion to 1 mg / ml, then place this dispersion in an ultrasonic oscillator and ultrasonicate for 15 min to form a uniformly dispersed spinning solution. After standing for defoaming, it is filled into the spinning solution storage tank, and the pore diameter of the spinneret is 0.06 mm;

[0027] Then, prepare the coagulation bath: The coagulation bath in this example is a mixed solution composed of N, N-dimethylacetamide (DMAc), water, and methanesulfonic acid (MSA). The volume ratio of DMAc to water is 10:1; the added concentration of MSA is 0.16 mol / L. First, mix DMAc and water evenly, then add MSA and stir well before use;

[0028] Finally, perform wet spinning: Use a syringe pump to pump the spinning solution into the coagulation bath through a wet spinning spinneret for coagulation and shaping. The advancing speed of the syringe pump is 2 ml / h. Fish out the pumped fibers, dry them, and wind and collect them with a polytetrafluoroethylene roller, and then seal and store them after completion. The SEM image of the PEDOT:PSS conductive fibers spun in this example is as Figure 1 shown. The fibers have an ultrafine diameter of about 890 nm, and for the first time, the preparation of pure PEDOT:PSS nanofibers relying on wet spinning technology is achieved, and its conductivity is 4036 ± 312 S / cm. Example 2

[0029] First, prepare the PEDOT:PSS spinning solution: Take the PEDOT:PSS aqueous dispersion stock solution (concentration is 13 mg / ml), then place this dispersion in an ultrasonic oscillator and ultrasonicate for 15 min to form a uniformly dispersed spinning solution. After standing for defoaming, load it into the spinning solution storage tank. The pore diameter of the spinneret is 0.26 mm;

[0030] Then, prepare the coagulation bath: The coagulation bath in this example is a mixed solution composed of DMAc, water, and MSA. The volume ratio of DMAc to water is 10:1; the added concentration of MSA is 0.01 mol / L. First, mix DMAc and water evenly, then add MSA and stir well before use;

[0031] Finally, perform wet spinning: Use a syringe pump to pump the spinning solution into the coagulation bath through a wet spinning spinneret for coagulation and shaping. The advancing speed of the syringe pump is 5 ml / h. Fish out the extruded fibers, dry them, and wind and collect them with a polytetrafluoroethylene roller, and then seal and store them after completion. The SEM image of the PEDOT:PSS conductive fibers spun in this example is as Figure 2 shown. The fibers have an ultrafine diameter of about 12 μm, and its conductivity is 1536 ± 107 S / cm. Example 3

[0032] First, prepare the PEDOT: PSS spinning solution: By the method of adding water for dilution, dilute the PEDOT: PSS aqueous dispersion to 6 mg / ml, and then place this dispersion in an ultrasonic oscillator and ultrasonicate for 15 min to form a uniformly dispersed spinning solution. After standing for degassing, it is filled into the spinning solution storage tank, and the pore diameter of the spinneret is 0.06 mm;

[0033] Then, prepare the coagulation bath: The coagulation bath in this example is a mixed solution composed of DMAc, water, and MSA. The volume ratio of DMAc to water is 10:1; the added concentration of MSA is 0.16 mol / L. First, mix DMAc and water evenly, and then add MSA and stir well for standby;

[0034] Finally, perform wet spinning: Use a syringe pump to pump the spinning solution through the wet spinning spinneret into the coagulation bath for coagulation and forming. The advancing speed of the syringe pump is 0.5 ml / h. The extruded fibers are fished out, dried, and wound and collected with a polytetrafluoroethylene roller, and then sealed and stored after completion. The SEM image of the PEDOT: PSS conductive fiber spun in this example is as Figure 3 shown. The fiber has an ultra-fine diameter of about 7 μm, and its conductivity is 1863 ± 232 S / cm. Example 4

[0035] First, prepare the PEDOT: PSS spinning solution: Take the original PEDOT: PSS aqueous dispersion (the concentration is 13 mg / ml), and then place this dispersion in an ultrasonic oscillator and ultrasonicate for 15 min to form a uniformly dispersed spinning solution. After standing for degassing, it is filled into the spinning solution storage tank, and the pore diameter of the spinneret is 0.26 mm;

[0036] Then, prepare the coagulation bath: The coagulation bath in this example is a mixed solution composed of DMAc, water, and MSA. The volume ratio of DMAc to water is 10:1; the added concentration of MSA is 0.16 mol / L. First, mix DMAc and water evenly, and then add MSA and stir well for standby;

[0037] Finally, perform wet spinning: Use a syringe pump to pump the spinning solution through the wet spinning spinneret into the coagulation bath for coagulation and forming. The advancing speed of the syringe pump is 5 ml / h. The extruded fibers are fished out, dried, and wound and collected with a polytetrafluoroethylene roller, and then sealed and stored after completion. The SEM image of the ultra-fine PEDOT: PSS conductive fiber spun in this example is as Figure 4 shown. The fiber has an ultra-fine diameter of about 13 μm, and its conductivity is 1675 ± 194 S / cm. Example 5

[0038] This example mainly takes the ultrafine PEDOT: PSS conductive fiber prepared in the above Example 4 as an example to prepare a micro-supercapacitor.

[0039] First, assemble the capacitor with the ultrafine PEDOT: PSS conductive fiber prepared in the above example. The fiber-based micro-supercapacitor in this example is an electric double-layer capacitor. The specific assembly method is as follows: Take two ultrafine PEDOT: PSS conductive fibers and arrange them side by side with a spacing of 1 - 2 mm as the two electrodes of the capacitor. Apply the conventional H3PO4-PVA electrolyte to the overlapping part of the two electrodes. The other two ends of the fibers are respectively coated with conductive silver paste for connecting to the external circuit. The assembled micro-supercapacitor is as shown in Figure 10 Figure a. Figure 10 Figure b shows a comparison diagram of a micro-supercapacitor assembled with the prepared conductive fiber and an adult's finger. Figure 10 Figure c shows a micro-supercapacitor array composed of 25 micro-supercapacitors in a 5×5 series-parallel connection. After charging, it generates a voltage of 5 V as shown in Figure 10 Figure e. Figure 10 Figure d shows a micro-supercapacitor array composed of 150 micro-supercapacitors in series. After charging, it can generate a high voltage of 135 V, as shown in Figure 10 Figure f. Comparative Example 1

[0040] First, prepare the PEDOT: PSS spinning solution: Take the PEDOT: PSS aqueous dispersion stock solution (concentration is 13 mg / ml), and then place this dispersion in an ultrasonic oscillator and ultrasonicate for 15 min to form a uniformly dispersed spinning solution. After standing and defoaming, it is loaded into the spinning solution storage tank. The pore diameter of the spinneret is 0.26 mm.

[0041] Then, prepare the coagulation bath: The coagulation bath in this example is a mixed solution composed of DMAc, water, and MSA. The volume ratio of DMAc to water is 10:1; the added concentration of MSA is 0.3 mol / L. First, mix DMAc and water evenly, and then add MSA and stir well for standby.

[0042] Finally, perform wet spinning: Use a syringe pump to pump the spinning solution through the wet spinning spinneret into the coagulation bath for solidification molding. The advancing speed of the syringe pump is 5 ml / h. The extruded fibers are fished out, dried, and wound and collected with a polytetrafluoroethylene roller, and then sealed and stored after completion. The SEM image of the PEDOT: PSS conductive fiber spun in this comparative example is as shown in Figure 5 Figure, the fiber has a relatively thick diameter of about 20 μm, and its conductivity is 832 ± 98 S / cm. Comparative Example 2

[0043] First, prepare the PEDOT: PSS spinning solution: Use a heating stirrer to concentrate the PEDOT: PSS aqueous dispersion to 25 mg / ml, and then place this dispersion in an ultrasonic oscillator and ultrasonicate for 15 min to form a uniformly dispersed spinning solution. After standing for degassing, it is loaded into the spinning solution storage tank, and the pore diameter of the spinneret is 0.26 mm;

[0044] Then, prepare the coagulation bath: The coagulation bath in this example is a mixed solution composed of DMAc, water, and MSA. The volume ratio of DMAc to water is 10:1; the added concentration of MSA is 0.16 mol / L. First, mix DMAc and water evenly, and then add MSA and stir well for standby;

[0045] Finally, perform wet spinning: Use a syringe pump to pump the spinning solution through the wet spinning spinneret into the coagulation bath for solidification molding, and the syringe pump propulsion speed is 5 ml / h. The extruded fibers are fished out, dried, and wound and collected with a polytetrafluoroethylene roller, and then sealed and stored after completion. The SEM image of the PEDOT: PSS conductive fibers spun in this comparative example is as Figure 6 shown. Although a relatively high spinning solution concentration can still be solidified into fibers, it is not conducive to fiber refinement. The prepared fibers have a large diameter of about 37 μm, and their conductivity is 1027 ± 131 S / cm. Comparative Example 3

[0046] First, prepare the PEDOT: PSS spinning solution: Take the original PEDOT: PSS aqueous dispersion solution (the concentration is 13 mg / ml), and then place this dispersion in an ultrasonic oscillator and ultrasonicate for 15 min to form a uniformly dispersed spinning solution. After standing for degassing, it is loaded into the spinning solution storage tank, and the spinneret pore diameter is 0.34 mm;

[0047] Then, prepare the coagulation bath: The coagulation bath in this example is a mixed solution composed of DMAc, water, and MSA. The volume ratio of DMAc to water is 10:1; the added concentration of MSA is 0.16 mol / L. First, mix DMAc and water evenly, and then add MSA and stir well for standby;

[0048] Finally, perform wet spinning: Use a syringe pump to pump the spinning solution through the wet spinning spinneret into the coagulation bath for solidification molding, and the syringe pump propulsion speed is 5 ml / h. The extruded fibers are fished out, dried, and wound and collected with a polytetrafluoroethylene roller, and then sealed and stored after completion. The SEM image of the PEDOT: PSS conductive fibers spun in this comparative example is as Figure 7As shown. An overly large spinneret aperture will also result in a relatively large fiber diameter. The prepared fiber has a large diameter of approximately 78 μm, and its conductivity is 935 ± 82 S / cm. Comparative Example 4

[0049] First, prepare the PEDOT:PSS spinning solution: Take the original PEDOT:PSS aqueous dispersion (with a concentration of 13 mg / ml), and then place this dispersion in an ultrasonic oscillator for 15 minutes of ultrasonic treatment to form a uniformly dispersed spinning solution. After standing for degassing, it is loaded into the spinning solution storage tank, and the spinneret aperture is 0.26 mm;

[0050] Then, prepare the coagulation bath: The coagulation bath in this example is a mixed solution composed of DMAc, water, and MSA. The volume ratio of DMAc to water is 10:1; the added concentration of MSA is 0.16 mol / L. First, mix DMAc and water evenly, and then add MSA and stir well for standby;

[0051] Finally, perform wet spinning: Use a syringe pump to pump the spinning solution through the wet spinning spinneret into the coagulation bath for solidification molding. The advancing speed of the syringe pump is 10 ml / h. The extruded fibers are fished out, dried, and wound and collected with a polytetrafluoroethylene roller, and then sealed and stored after completion. The SEM image of the PEDOT:PSS conductive fiber spun in this comparative example is as Figure 8 shown. When the aperture of the spinneret is fixed, too fast an advancing speed results in a larger amount of spinning solution extruded in the same time, and the prepared fibers will be thicker. The fiber has a large diameter of approximately 70 μm, and its conductivity is 764 ± 63 S / cm. Comparative Example 5

[0052] First, prepare the PEDOT:PSS spinning solution: By the method of adding water for dilution, dilute the PEDOT:PSS aqueous dispersion to 0.5 mg / ml, and then place this dispersion in an ultrasonic oscillator for 15 minutes of ultrasonic treatment to form a uniformly dispersed spinning solution. After standing for degassing, it is loaded into the spinning solution storage tank, and the spinneret aperture is 0.06 mm;

[0053] Then, prepare the coagulation bath: The coagulation bath in this example is a mixed solution composed of DMAc, water, and MSA. The volume ratio of DMAc to water is 10:1; the added concentration of MSA is 0.005 mol / L. First, mix DMAc and water evenly, and then add MSA and stir well for standby;

[0054] Finally, wet spinning is carried out: The spinning solution is pumped into the coagulation bath through the wet spinning spinneret by an injection pump for coagulation molding, and the advancing speed of the injection pump is 0.2 ml / h. The extruded fibers are fished out, dried, wound and collected with a polytetrafluoroethylene roller, and then stored in a sealed manner after completion. In this comparative example, due to reasons such as the thin concentration of the spinning solution, the small addition amount of MSA, and the slow advancing speed of the injection pump, PEDOT:PSS conductive fibers cannot be continuously prepared. Comparative Example 6

[0055] First, prepare the PEDOT:PSS spinning solution: Take the PEDOT:PSS aqueous dispersion stock solution (the concentration is 13 mg / ml), and then place this dispersion in an ultrasonic oscillator for 15 min of ultrasonic treatment to form a uniformly dispersed spinning solution. After standing and degassing, it is filled into the spinning solution storage tank, and the pore diameter of the spinneret is 0.26 mm;

[0056] Then, prepare the coagulation bath: The coagulation bath in this example is a mixed solution composed of DMAc, water and FeCl3. The volume ratio of DMAc to water is 5:1; the added concentration of FeCl3 is 0.02 mol / L. First, mix DMAc and water evenly, and then add FeCl3 and stir well for standby;

[0057] Finally, wet spinning is carried out: The spinning solution is pumped into the coagulation bath through the wet spinning spinneret by an injection pump for coagulation molding, and the advancing speed of the injection pump is 5 ml / h. The extruded fibers are fished out, dried, wound and collected with a polytetrafluoroethylene roller, and then stored in a sealed manner after completion. The SEM image of the PEDOT:PSS conductive fibers spun in this comparative example is as Figure 9 shown. Adding metal ions to the coagulation bath of the DMAc and water system can also prepare PEDOT:PSS conductive fibers by wet spinning. However, due to the strong cross-linking effect of metal cations, it is not conducive to the removal of PSS and the refinement of fibers. The fiber diameter is relatively thick, about 78 μm, and its conductivity is 61.3 ± 18 S / cm.

Claims

1. A preparation method of ultrafine PEDOT: PSS conductive fibers, characterized in that, It includes the following steps: Step 1: Prepare a PEDOT: PSS spinning solution with a water dispersion concentration of 1 - 13 mg / mL; Step 2: Use an injection pump to evenly pump the spinning solution into a mixed coagulation bath containing N, N - dimethylacetamide (DMAc) and water through a wet spinning spinneret for solidification molding. Methanesulfonic acid (MSA) is added to the mixed coagulation bath of DMAc and water in a proportion of 0.01 - 0.16 mol / L; the solidified fibers are fished out, dried, cooled and collected to obtain ultrafine PEDOT: PSS conductive fibers for micro - supercapacitors; the advancing speed of the injection pump is 0.5 - 5 ml / h; the pore diameter of the spinneret is 0.06 - 0.26 mm.

2. The preparation method of the ultrafine PEDOT:PSS conductive fiber according to claim 1, characterized in that, In Step 1, the PEDOT: PSS spinning solution is prepared by oscillating the PEDOT: PSS water dispersion with an ultrasonic oscillator for 15 min at room temperature, mixing evenly and then standing for degassing to obtain a uniform spinning solution.

3. The preparation method of the ultrafine PEDOT:PSS conductive fiber according to claim 1, characterized in that, In Step 2, in the mixed coagulation bath, the volume ratio of DMAc to water is 10:

1.

4. A micro-supercapacitor, characterized in that, It is prepared from the ultrafine PEDOT: PSS conductive fibers obtained by the preparation method described in any one of claims 1 - 3.

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