Conductive polymers and their use in the preparation of flexible supercapacitors

Abstract

The application discloses a conductive polymer and application thereof in preparation of a flexible super capacitor, and electrochemical polymerization is carried out on EDOT monomers and EDOT-ME monomers, so that urethane groups are grafted into side chains of PEDOT polymers; hydrogen bond forces can be formed between polymer molecular chains through the urethane groups of the side chains, not only improving the interaction between the polymer chains, but also constructing rich pore structures; the material can maintain the integrity of the electrode material under mechanical stress, and can also maintain good electrochemical performance of the polymer material in the ion doping / dedoping process.

Description

Technical Field

[0001] This invention relates to a novel conductive polymer for use in flexible supercapacitor materials, a method for preparing the polymer, and its application in supercapacitors. Background Technology

[0002] Supercapacitors have attracted widespread attention due to their long lifespan, pollution-free operation, safety, and excellent mechanical properties. Compared to traditional capacitors, supercapacitors possess extremely high energy density, making them ideal as energy supply devices for electronic devices and meeting the demand for new sustainable energy sources. Simultaneously, with the development of next-generation wearable and implantable flexible electronic materials, the physical form of electronic devices has shifted from rigid to flexible. Flexible electrode technology, as an energy supply device, is a prerequisite for the widespread application of flexible electronic devices. Therefore, flexible supercapacitors have very high potential as energy storage devices.

[0003] Among various supercapacitor electrode materials, pseudocapacitive materials achieve energy storage through rapid and reversible redox reactions occurring on the electrode surface and in the bulk phase near the surface. Conductive polymers (CPs) have attracted attention due to their ability to rapidly switch between oxidized and reduced states, structural stability, and high conductivity. Poly(3,4-ethylenedioxythiophene) (PEDOT) is a particularly promising CP, exhibiting high stability and high conductivity during charge and discharge processes. Summary of the Invention

[0004] The purpose of this invention is to provide a conductive polymer for flexible supercapacitors, a method for preparing the same, and a method for preparing the same. This invention grafts urethane groups onto the side chains of a PEDOT polymer. Hydrogen bonds can be formed between the polymer molecular chains through the urethane groups on the side chains. This allows the material to maintain the integrity of the electrode material under mechanical stress, while also maintaining good electrochemical performance during ion doping / dedoping.

[0005] The technical solution of this invention is as follows:

[0006] In a first aspect, the present invention provides a conductive polymer, which is prepared by the following method:

[0007] The monomers shown in Formula 1 and Formula 2, along with the electrolyte, are dissolved in a mixed solvent of acetonitrile and dichloromethane to obtain a monomer solution. Using this monomer solution as the electrolyte, Ag / AgCl as the reference electrode, platinum wire as the counter electrode, and a PET-ITO flexible film as the working electrode, the conductive polymer is prepared via electrochemical polymerization (cyclic voltammetry / electrodeposition). The electrolyte is one or more of tetrabutylammonium hexafluorophosphate, lithium perchlorate, lithium chloride, and lithium tetrafluoroborate. The amount of the monomer shown in Formula 1 is 10-90% (preferably 40%) of the total amount of the monomers shown in Formula 1 and Formula 2. The concentration of the monomer shown in Formula 1 in the monomer solution is 1-10 mmol / L (preferably 3 mmol / L).

[0008]

[0009] Furthermore, the concentration of the electrolyte in the monomer solution is 0.001–1 M (preferably 0.1 M). In one embodiment of the present invention, the electrolyte is tetrabutylammonium hexafluorophosphate.

[0010] In this invention, PEMEx is obtained by copolymerizing 3,4-ethylenedioxythiophene (EDOT) monomer with (2,3-Dihydrothieno[3,4-b][1,4]dioxin-2-yl)methyl ethylcarbamate (EDOT-ME) monomer via electrochemical polymerization. This grafts urethane groups onto the side chains of the PEDOT polymer, creating hydrogen bonds between polymer molecules. Therefore, the PEDOT-based conductive polymer electrode material not only maintains good rate performance and stability but also possesses superior mechanical properties.

[0011] The synthesis route of the PEDOT-based conductive polymer electrode material of the present invention is as follows:

[0012]

[0013] Random copolymerization. Where x refers to the proportion of each of the two monomers, which is any number from 0.1 to 0.9.

[0014] The method for preparing a PEDOT-based conductive polymer electrode material is characterized in that: the conductive polymer material is obtained by electrochemical polymerization of EDOT monomer and EDOT-ME monomer in a three-electrode system.

[0015] Furthermore, in the mixed solvent of acetonitrile and dichloromethane, the volume ratio of acetonitrile to dichloromethane is 1:0.1-9 (preferably 1:0.67).

[0016] In one embodiment of the present invention, the electrochemical polymerization method is cyclic voltammetry. The parameters of the cyclic voltammetry are: a minimum voltage of -0.3 to 0 V, a maximum voltage of 1.4 to 1.8 V, and a cycle count of 1 to 30.

[0017] Specifically, the parameters of the cyclic voltammetry method are: minimum voltage of -0.3V, maximum voltage of 1.6V, scan rate of 0.1V / s, and number of cycles of 10.

[0018] The electrochemical polymerization method can also be an electrodeposition method. The parameters of the electrodeposition method are: voltage 0.6–1.4V, deposition time 1–500 seconds.

[0019] Secondly, this invention provides an application of the aforementioned conductive polymer in the fabrication of flexible supercapacitors (as electrode materials).

[0020] Compared with existing technologies, the main advantages of this invention are: grafting urethane groups onto the side chains of PEDOT polymers, thereby forming hydrogen bonds between polymer molecules. This not only enhances the interaction between polymer chains but also creates a rich porous structure. Therefore, PEDOT-based conductive polymer electrode materials not only maintain good rate performance and stability during ion doping / dedoping but also retain excellent electrochemical performance under mechanical stress. Attached Figure Description

[0021] Figure 1 For PEME 0.6 Constant current charge-discharge curves of electrode materials at different current densities

[0022] Figure 2 For PEME 0.6 Charge-discharge curves of electrode materials at different bending angles

[0023] Figure 3 The galvanostatic charge-discharge curves of the PEME0 electrode material at different current densities

[0024] Figure 4 For PEME 0.2 Image of electrode material after ultrasonic stripping

[0025] Figure 5 For PEME 0.4 Image of electrode material after ultrasonic stripping

[0026] Figure 6 For PEME 0.6 Image of electrode material after ultrasonic stripping

[0027] Figure 7 For PEME 0.8Image of electrode material after ultrasonic stripping

[0028] Figure 8 This is a diagram showing the state of the PEME0 electrode material after ultrasonic exfoliation.

[0029] Figure 9 For PEME 0.6 Infrared spectra of polymer and EDOT-ME monomer Detailed Implementation

[0030] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto:

[0031] Example 1:

[0032] The preparation method of the PEDOT-based conductive polymer in this embodiment includes the following steps:

[0033] (1) Preparation of monomer solution: 1 mmol of EDOT-ME monomer (refer to CRSzczepanski, T. Darmanin, F. Guittard, Using poly(3,4-ethylenedioxythiophene) containing a carbamate linker as a platform to develop electrodeposited surfaces with tunable wettability and adhesion, RSC Advances. 5 (2015) 89407-89414). https: / / doi.org / 10.1039 / c5ra17952a. Preparation), 4 mmol of EDOT monomer and 0.1 M tetrabutyl hexafluorophosphate electrolyte were added to 1 L of acetonitrile / dichloromethane in a volume ratio of 3:2 and ultrasonically mixed for 25 min to obtain a monomer solution;

[0034] (2) Preparation of PEDOT-based conductive polymer: 10 mL of the above solution was added to the electrolytic cell reaction cell. Using Ag / AgCl as the reference electrode, platinum wire as the counter electrode, and PET-ITO flexible film as the working electrode, the polymer was prepared by cyclic voltammetry, with a voltage range of -0.3 to 1.6 V, a scan rate of 0.1 V / s, and 10 cycles.

[0035] (3) The above electrode material was immersed in a solution with a volume ratio of acetonitrile / dichloromethane of 3:2 for cleaning and then dried to obtain a conductive polymer electrode material, named PEME. 0.2 .

[0036] Example 2:

[0037] The preparation method of the PEDOT-based conductive polymer in this embodiment includes the following steps:

[0038] (1) Preparation of monomer solution: 2 mmol of EDOT-ME monomer, 3 mmol of EDOT monomer and 0.1 M of tetrabutylammonium hexafluorophosphate electrolyte were added to 1 L of solvent with a volume ratio of acetonitrile / dichloromethane of 3:2 and ultrasonically mixed for 25 min to obtain monomer solution;

[0039] (2) Preparation of PEDOT-based conductive polymer: 10 mL of the above solution was added to the electrolytic cell reaction cell. Using Ag / AgCl as the reference electrode, platinum wire as the counter electrode, and PET-ITO flexible film as the working electrode, the polymer was prepared by cyclic voltammetry, with a voltage range of -0.3 to 1.6 V, a scan rate of 0.1 V / s, and 10 cycles.

[0040] (3) The above electrode material was immersed in a solution with a volume ratio of acetonitrile / dichloromethane of 3:2 for cleaning and then dried to obtain a conductive polymer material, named PEME. 0.4 .

[0041] Example 3:

[0042] The preparation method of the PEDOT-based conductive polymer in this embodiment includes the following steps:

[0043] (1) Preparation of monomer solution: 3 mmol of EDOT-ME monomer, 2 mmol of EDOT monomer and 0.1 M of tetrabutylammonium hexafluorophosphate electrolyte were added to 1 L of solvent with a volume ratio of acetonitrile / dichloromethane of 3:2 and ultrasonically mixed for 25 min to obtain monomer solution;

[0044] (2) Preparation of PEDOT-based conductive polymer: 10 mL of the above solution was added to the electrolytic cell reaction chamber.

[0045] The polymer was prepared by cyclic voltammetry using Ag / AgCl as the reference electrode, platinum wire as the counter electrode, and PET-ITO flexible film as the working electrode. The voltage range was -0.3 to 1.6 V, the scan rate was 0.1 V / s, and the number of cycles was 10.

[0046] (3) The above electrode material was immersed in a solution with a volume ratio of acetonitrile / dichloromethane of 3:2 for cleaning and then dried to obtain a conductive polymer material, named PEME. 0.6 .

[0047] Example 4:

[0048] The preparation method of the PEDOT-based conductive polymer in this embodiment includes the following steps:

[0049] (1) Preparation of monomer solution: 4 mmol of EDOT-ME monomer, 1 mmol of EDOT monomer and 0.1 M of tetrabutylammonium hexafluorophosphate electrolyte were added to 1 L of solvent with a volume ratio of acetonitrile / dichloromethane of 3:2 and ultrasonically mixed for 25 min to obtain monomer solution.

[0050] (2) Preparation of PEDOT-based conductive polymer: 10 mL of the above solution was added to the electrolytic cell reaction chamber.

[0051] The polymer was prepared by cyclic voltammetry using Ag / AgCl as the reference electrode, platinum wire as the counter electrode, and PET-ITO flexible film as the working electrode. The voltage range was -0.3 to 1.6 V, the scan rate was 0.1 V / s, and the number of cycles was 10.

[0052] (3) The above electrode material was immersed in a solution with a volume ratio of acetonitrile / dichloromethane of 3:2 for cleaning and then dried to obtain a conductive polymer material, named PEME. 0.8 .

[0053] Example 5: Constant Current Charge-Discharge Performance Test of Polymer Thin Film

[0054] Using an electrochemical workstation to study PEME 0.6 The electrode material was subjected to constant current charge-discharge testing. The test method was as follows: 0.1M tetrabutylammonium hexafluorophosphate was added to a 10mL volumetric flask and diluted to volume with chromatographic grade acetonitrile to serve as a blank supporting electrolyte solution. Using the blank electrolyte solution as the test solution, a three-electrode system was constructed with the polymer film as the working electrode, a platinum wire as the counter electrode, and Ag / AgCl as the reference electrode. The test voltage range was 0V–1.4V, and the current density during the test was 0.1mA / cm². -2 0.5mA / cm -2 1mA / cm -2 2mA / cm -2 and 5mA / cm -2 Test results attached. Figure 1 As shown, its specific capacitance at different current densities is 7.47, 7.28, 7.14, 6.97, and 6.89 mF / cm, respectively. 2 .

[0055] Example 6: Constant current charge-discharge test of polymer film under different bending angles

[0056] PEME was tested using an electrochemical workstation. 0.6The electrochemical performance of the electrode material under bending conditions was tested using the following method: A three-electrode system was constructed using the blank electrolyte solution described above as the test solution, polymer films at different bending angles as the working electrode, platinum wire as the counter electrode, and Ag / AgCl as the reference electrode. The test voltage range was 0V–1.4V, and the bending angles were 0°, 30°, 60°, and 90°. The test results are attached. Figure 2 As shown, the electrode material does not lose specific capacity when bent at 90°.

[0057] Example 7: Synthesis and testing of a side-chain-free polymer as a comparative example

[0058] The polymerization conditions were the same as in Example 1, and the polymer material was named PEME0. The monomer concentration was 5 mmol / LEDOT. The constant current charge-discharge performance test was performed as in Example 5, and the test results are attached. Figure 3 As shown, at current densities of 0.1, 0.5, 1, 2, and 5 mA / cm², 2 The specific capacities were 6.68, 6.49, 6.47, 5.32, and 3.57 mF / cm³, respectively. 2 .

[0059] Example 8:

[0060] PEME with certain side chains 0.2 PEME 0.4 PEME 0.6 PEME 0.8 The mechanical properties of the comparative PEMEO electrode material, such as material integrity and adhesion to machinery, were characterized by ultrasonic peel testing. The test results are shown in the attached figures. Figure 4 Appendix Figure 5 Appendix Figure 6 Appendix Figure 7 and attached Figure 8 As shown in the figure. Test results indicate that an appropriate side chain density can affect its mechanical properties to some extent. Compared with the comparative example PEME0, the copolymer films all exhibited superior adhesion and integrity. Among them, PEME... 0.6 Electrode materials show the most significant effects and have great application potential.

[0061] Example 9:

[0062] EDOT-ME monomer and PEME in Example 1 x The polymer film underwent infrared spectroscopy testing, and the results are attached. Figure 9 As shown. Infrared spectral data indicate that the copolymer PEMEX has a C=O absorption peak (1640 cm⁻¹) specific to EDOT-ME. -1 This indicates that the copolymer was successfully prepared.

[0063] The above data shows that PEDOT-based conductive polymer materials have excellent rate performance, at 5 mA / cm². -2 It retains 92.2% capacity even at high current densities. Furthermore, its specific capacity remains unchanged even at a bending angle of 90°. Meanwhile, the side-chain-free polymer exhibits a capacity retention of 92.2% at 5 mA / cm². -2 At high current densities, it retains only 53.4% ​​of its capacity. Furthermore, the addition of side chains significantly improves the material's mechanical properties, such as flexibility, material integrity, and adhesion.

[0064] In summary, PEDOT-based conductive polymer materials possess not only excellent mechanical properties but also good electrochemical performance. They have significant application value and potential in the field of flexible electrode materials.

[0065] In the embodiments described above, any modifications, equivalents, substitutions, or improvements to the material ratios and processes involved in this invention should be included within the scope of protection of this invention.

Claims

1. A conductive polymer, characterized in that... The conductive polymer is prepared according to the following method: The monomers shown in Formula 1 and Formula 2, along with the electrolyte, are dissolved in a mixed solvent of acetonitrile and dichloromethane to obtain a monomer solution. Using this monomer solution as the electrolyte, Ag / AgCl as the reference electrode, platinum wire as the counter electrode, and a PET-ITO flexible film as the working electrode, the conductive polymer is prepared by electrochemical polymerization. The electrolyte is one or more of tetrabutylammonium hexafluorophosphate, lithium perchlorate, lithium chloride, and lithium tetrafluoroborate. The amount of the monomer shown in Formula 1 is 10-90% of the total amount of the monomers shown in Formula 1 and Formula 2. The concentration of the monomer shown in Formula 1 in the monomer solution is 1-10 mmol / L. The electrochemical polymerization method is cyclic voltammetry. 。 2. The conductive polymer as described in claim 1, characterized in that: The concentration of the electrolyte in the monomer solution is 0.001~1M.

3. The conductive polymer as described in claim 1, characterized in that: The electrolyte is tetrabutylammonium hexafluorophosphate.

4. The conductive polymer as described in claim 1, characterized in that: In the mixed solvent of acetonitrile and dichloromethane, the volume ratio of acetonitrile to dichloromethane is 1:0.1-9.

5. The conductive polymer as described in claim 1, characterized in that: The parameters of the cyclic voltammetry method are: the minimum voltage is -0.3~0V, the maximum voltage is 1.4~1.8V, and the number of cycles is 1~30.

6. The conductive polymer as described in claim 1, characterized in that: The amount of substance of the monomer shown in Formula 1 is 40% of the total amount of substance of the monomer shown in Formula 1 and the monomer shown in Formula 2.

7. The application of the conductive polymer as described in any one of claims 1-6 in the preparation of flexible supercapacitors.

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