A method for preparing a high-density and high-stability conductive polymer thin film based on electrochemical polymerization

Abstract

The application discloses a preparation method of a high-density and high-stability conductive polymer film based on electrochemical polymerization, and comprises the following steps: using an oxidant solution and a BFDO monomer solution to pretreat a formed foil to obtain a working electrode, then immersing the working electrode and a reference electrode into an electrolyte to perform electrochemical oxidation polymerization, and obtaining the high-density and high-stability conductive polymer film based on electrochemical polymerization. The pretreated formed foil containing N-type conductive polymer PBFDO is prepared by using a chemical in-situ polymerization method on the formed foil, and when the pretreated formed foil is applied in the field of capacitors, the conductivity and electron transport capacity of the capacitor can be improved, and the stability problem caused by the coupling of positive and negative charges in the traditional capacitor is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of conductive polymers, in particular to a preparation method of a high-density and high-stability conductive polymer film based on electrochemical polymerization. BACKGROUND

[0002] At present, conductive polymers have a wide range of applications in the field of organic electronics. Since the N-type conductive polymer PBFDO (polybenzo[1,2-B:4,5-B']dioxole-2,6(3H,7H)-dione) with ultra-high conductivity and high stability was reported (Nature 2022, 611, 271-277), the preparation of high-density films of PBFDO and its applications have attracted more and more attention. Taking sheet-type laminated aluminum electrolytic capacitors as an example, aluminum electrolytic capacitors based on PBFDO have great application potential in consumer electronics, computers, information communication and automotive electronics. However, PBFDO is a rigid linear polymer molecule, and the irregular arrangement of the rigid chain during the film formation process of PBFDO prepared by chemical oxidative polymerization reaction will cause large gaps between the molecular chains, and there are certain problems in the quality and stability of the film. In addition, due to the non-uniformity in the reaction process and the rigid structure of the material, the density and stability of the PBFDO film prepared by the chemical in-situ polymerization method have certain problems, and the film is easy to fall off when exposed to a humid environment and a DMSO solvent atmosphere for a long time. In the preparation and actual application process of aluminum electrolytic capacitors, the above-mentioned situations will cause the leakage current (LC) of the aluminum electrolytic capacitors to increase and the equivalent series resistance (ESR) to increase, and this change is irreversible. Therefore, improving the quality and stability of the PBFDO film is of great significance for the practical application of PBFDO, especially the wide application of sheet-type laminated aluminum electrolytic capacitors with high reliability and high performance. SUMMARY

[0003] Therefore, it is necessary to provide a preparation method of a high-density and high-stability conductive polymer film based on electrochemical polymerization, and the prepared film has a more dense and smooth surface morphology. The aluminum electrolytic capacitor prepared by using the method has the advantages of low leakage current (LC), small equivalent series resistance (ESR) and stable capacitance, and has significant economic value and social benefits.

[0004] An object of the present application is to provide a preparation method of a high-density and high-stability conductive polymer film based on electrochemical polymerization, comprising the following steps:

[0005] The working electrode is obtained by pretreating the formation foil with a treatment solution, and then the working electrode, the reference electrode and the counter electrode are immersed in an electrolyte, and electrochemical polymerization is carried out by a three-electrode system to obtain a high-density and high-stability conductive polymer film based on electrochemical polymerization.

[0006] wherein the treatment liquid is selected from an oxidant solution and a BFDO monomer (benzo[1,2-B:4,5-B']difuran-2,6(3H,7H)-dione, CAS: 30272-74-3) solution;

[0007] or

[0008] the treatment liquid is selected from a PBFDO (polybenzo[1,2-B:4,5-B']difuran-2,6(3H,7H)-dione) solution.

[0009] In one aspect of the present application, the pretreatment comprises the following steps:

[0010] The pretreated formation foil is obtained by immersing the formation foil into the PBFDO solution, drying, and repeating the above steps for several times.

[0011] In another aspect of the present application, the pretreatment comprises the following steps:

[0012] The pretreated formation foil is obtained by immersing the formation foil into the oxidant solution, drying, immersing the formation foil into the BFDO monomer solution, drying, and repeating the above steps for several times.

[0013] In another aspect of the present application, the pretreatment comprises the following steps:

[0014] The pretreated formation foil is obtained by immersing the formation foil into the PBFDO solution, drying, and repeating the above steps for several times.

[0015] Specifically, the pretreated formation foil containing N-type conductive polymer PBFDO can be obtained by immersing the formation foil directly into the PBFDO solution in one step; the pretreated formation foil containing N-type conductive polymer PBFDO can be prepared by immersing the formation foil into the oxidant solution and the BFDO monomer solution respectively through the chemical in-situ polymerization method.

[0016] Specifically, the time for immersing the formation foil into the PBFDO solution is 4-20s.

[0017] Specifically, the time for immersing the formation foil into the oxidant solution is 4-20s.

[0018] Specifically, the time for immersing the formation foil into the BFDO monomer solution is 4-20s.

[0019] Further, the oxidant is selected from one or more of metal salt oxidants, oxides, peroxides, quinone compounds, and acid anhydride compounds.

[0020] The metal salt oxidants include, but are not limited to, ferric chloride and copper acetate.

[0021] The oxides include, but are not limited to, selenium dioxide, copper oxide, cuprous oxide.

[0022] The peroxides include, but are not limited to, hydrogen peroxide, tert-butyl hydroperoxide.

[0023] The quinone compounds include, but are not limited to, 2,3,5,6-tetramethyl-1,4-benzoquinone, 1,4-benzoquinone, 2-(10-hydroxydecyl)-5,6-dimethoxy-3-methyl-1,4-benzoquinone.

[0024] The anhydride compounds include, but are not limited to, acetic anhydride, maleic anhydride, benzoic anhydride.

[0025] Further, the concentration of the PBFDO solution is 3-20 mg / mL.

[0026] Further, the concentration of the BFDO monomer solution is 5-15 mg / mL.

[0027] Further, the number of repetitions is 1-30 times.

[0028] Specifically, by using the pretreated formation foil containing the N-type conductive polymer PBFDO prepared by the above process as a working electrode to perform electrochemical polymerization, a conductive polymer thin film with high density and high stability is further obtained.

[0029] Further, a three-electrode system is used in the electrochemical oxidative polymerization. In the three-electrode system, a working electrode, a counter electrode, and a reference electrode are included. The working electrode is the pretreated formation foil, the counter electrode is selected from one or more of platinum, graphite electrodes, and the reference electrode is selected from one or more of saturated calomel electrode, silver chloride electrode, and mercury / mercurous sulfate electrode.

[0030] Further, the electrochemical oxidative polymerization method uses one of constant voltage method, constant current method, and cyclic voltammetry method.

[0031] Specifically, in the constant voltage method, the oxidation potential is 0.3-3.0 V, and the oxidation polymerization time is 5-200 min.

[0032] Specifically, in the constant current method, the oxidation current is 0.1 μA-10 mA, and the oxidation polymerization time is 5-200 min.

[0033] Specifically, in the cyclic voltammetry method, the voltage scanning range is -1.0-3.0 V, the scanning rate is 20-100 mV / s, and the number of cycles is 10-5000 times.

[0034] Further, the electrolyte is selected from a solution containing EDOT monomer (3,4-ethylenedioxythiophene) and its derivatives;

[0035] The concentration of the solution is 5-300 mg / mL.

[0036] Specifically, the EDOT monomer and its derivatives include but are not limited to 3,4-ethylenedioxythiophene (CAS: 126213-50-1), 2-methyl-2,3-dihydro-thieno[3,4-B]-1,4-dioxin (CAS: 126235-11-8), 2-ethyl-2,3-dihydro-thieno[3,4-B]-1,4-dioxin (CAS: 1226799-20-7).

[0037] Specifically, the electrolyte prepared by the application is used for electrochemical polymerization, different electrolyte systems can be customized according to different application scenarios, and capacitor products meeting different parameters and requirements can be prepared, which has wide practicability.

[0038] The application also provides application of the high-density and high-stability conductive polymer film based on electrochemical polymerization prepared by the preparation method in the fields of flexible electrodes, super capacitors and aluminum electrolytic capacitors.

[0039] Specifically, the high-density and high-stability conductive polymer film based on electrochemical polymerization has wide application prospects in many fields such as super capacitors and electrolytic capacitors. Taking aluminum electrolytic capacitors as an example, the formed foil obtained by processing is coated with carbon paste, silver paste, laminated and bonded, encapsulated with epoxy resin and aged, and then a sheet-type laminated aluminum electrolytic capacitor with low leakage current (LC), low equivalent series resistance (ESR) and high stability is prepared.

[0040] The application has the following beneficial effects:

[0041] 1、The present application can meet the requirement of generating conductive polymer film in-situ inside the pore directly, has higher surface coverage, strong substrate adhesion, can effectively avoid the problem that the conductive polymer cannot enter the pore efficiently due to too large particle size, has the advantages of saving raw materials, avoiding the problem that the monomer and oxidizing agent cannot be reused after being blended, etc., meets the requirements of large-scale assembly line preparation and actual application; in addition, due to the poor solubility of the BFDO monomer in the oxidizing agent solution, the method of the present application can avoid the mutual introduction of impurities between the BFDO monomer solution and the oxidizing agent solution during the in-situ polymerization process. When it is applied in the field of aluminum electrolytic capacitors, the conductivity and electron transport capacity of the capacitor can be improved, and the stability problem caused by the coupling of positive and negative charges is greatly improved. In addition, due to the excellent moisture resistance of the N-type conductive polymer PBFDO, the high temperature and high humidity stability of the prepared aluminum electrolytic capacitor is also greatly improved, realizing the successful preparation of aluminum electrolytic capacitors with high capacity, high stability and low ESR.

[0042] 2、By performing electrochemical polymerization of EDOT on the pretreated formation foil containing N-type conductive polymer PBFDO, the pretreated formation foil containing N-type conductive polymer PBFDO is modified in a low-cost, non-toxic and low-pollution manner without introducing other impurities, a conductive polymer film with high compactness, high stability and high conductivity is prepared, compared with the prior art, the method can effectively avoid the performance problem caused by the application of P-type conductive polymer to the negative electrode of the capacitor, and at the same time, the advantages of the conductive polymer PBFDO layer are utilized; in addition, the conductive polymer film obtained by the method provided by the present application can effectively reduce the LC and ESR of the aluminum electrolytic capacitor when applied in the field of aluminum electrolytic capacitors, greatly improve the device performance and stability, and has significant economic value and social benefits. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 SEM test figures of formation foils D1-D6 are shown;

[0044] Figure 2 SEM test figures of conductive polymer films M1-M7 are shown. DETAILED DESCRIPTION

[0045] In order to more clearly illustrate the technical solutions of the present application, the following examples are listed. The raw materials, reactions and post-treatment means appearing in the examples are all common raw materials on the market and technical means well known to those skilled in the art, unless otherwise stated.

[0046] BFDO monomer: purchased from Henan Alpha Chemical Co., Ltd., CAS: 30272-74-3.

[0047] Chemical foils: purchased from Huafeng Electronic Aluminum Foil Co., Ltd., low-voltage positive foils.

[0048] Selenium dioxide: purchased from Shanghai Aldrin Biochemical Technology Co., Ltd., CAS: 7446-08-4.

[0049] PBFDO solution: prepared according to the literature “Tang Haoran, et al., A solution-processed n-type conducting polymer with ultrahigh conductivity. Nature, 2022, 611, 271-277.”

[0050] Preparation Example 1

[0051] The preparation method of the pretreated chemical foils includes the following steps:

[0052] The BFDO monomer was dissolved in DMSO solution to obtain a BFDO monomer solution with a concentration of 10 mg / mL;

[0053] Selenium dioxide was dissolved in water to obtain an oxidant solution with a concentration of 10 mg / mL;

[0054] The chemical foils were immersed in the oxidant solution for 20 s, then taken out and blown dry at 40°C for 15 min, immersed in the BFDO monomer solution for 10 s, then taken out and vacuum dried at 80°C for 15 min. After repeating the above steps for 10 cycles, 10 times of pretreated chemical foils D1 were obtained.

[0055] Preparation Example 2

[0056] The preparation method of the pretreated chemical foils includes the following steps:

[0057] The BFDO monomer was dissolved in DMSO solution to obtain a BFDO monomer solution with a concentration of 12 mg / mL;

[0058] Copper acetate was dissolved in ethanol to obtain an oxidant solution with a concentration of 6 mg / mL;

[0059] The chemical foils were immersed in the oxidant solution for 5 s, then taken out and vacuum dried at 80°C for 15 min, immersed in the BFDO monomer solution for 5 s, then taken out and air-dried at room temperature for 15 min. After repeating the above steps for 10 cycles, 10 times of pretreated chemical foils D2 were obtained.

[0060] Preparation Example 3

[0061] A method for preparing a pretreated formation foil, comprising the following steps:

[0062] BFDO monomer was dissolved in DMSO solution to obtain a BFDO monomer solution with a concentration of 10 mg / mL;

[0063] Selenium dioxide was dissolved in isopropyl alcohol to obtain an oxidant solution with a concentration of 10 mg / mL;

[0064] The formation foil was immersed in the oxidant solution for 5 s, and after being taken out, it was vacuum dried at 80°C for 15 min, then immersed in the BFDO monomer solution for 5 s, and after being taken out, it was air-dried at room temperature for 15 min, and the above steps were repeated for 10 cycles. Then the formation foil was immersed in the finished PEDOT:PSS solution (commercially available, aqueous solution with a purity of 1.5 wt%) for 5 s, and after being immersed in deionized water for 5 s and vacuum dried at 80°C, the pretreated formation foil D3 with 10 times of pretreatment was obtained.

[0065] Preparation Example 4

[0066] A method for preparing a pretreated formation foil, comprising the following steps:

[0067] BFDO monomer was dissolved in DMSO solution to obtain a BFDO monomer solution with a concentration of 10 mg / mL;

[0068] Selenium dioxide was dissolved in isopropyl alcohol to obtain an oxidant solution with a concentration of 10 mg / mL;

[0069] The formation foil was immersed in the oxidant solution for 5 s, and after being taken out, it was vacuum dried at 80°C for 15 min, then immersed in the BFDO monomer solution for 5 s, and after being taken out, it was air-dried at room temperature for 15 min, and the above steps were repeated for 10 cycles. Then the formation foil was immersed in the finished PEDOT:PSS solution (commercially available, aqueous solution with a purity of 1.5 wt%) for 5 s, and after being immersed in deionized water for 5 s and vacuum dried at 80°C, the pretreated formation foil D3 with 10 times of pretreatment was obtained.

[0070] Preparation Example 5

[0071] A method for preparing a pretreated formation foil, comprising the following steps:

[0072] The formation foil was immersed in the PBFDO solution (10 mg / mL) at room temperature and normal pressure for 3 min, and after being taken out, it was washed with deionized water and vacuum dried at 80°C to obtain the pretreated formation foil D5.

[0073] Comparative Preparation Example 1

[0074] A method for preparing a pretreated formation foil, comprising the following steps:

[0075] BFDO monomer (150 mg) and selenium dioxide (9 mg) were dissolved in 10 mL of DMSO solution, and the prepared foil was immersed in the above solution at room temperature under normal pressure for 3 min, and then taken out, washed with deionized water, and dried at 80°C under vacuum to obtain a pretreated formation foil D6.

[0076] The above mixed solution gradually gels within 10 min at room temperature, and cannot be used again, resulting in loss of raw materials, and thus cannot meet the requirements of continuous and large-scale production in actual application, and thus no subsequent electrochemical polymerization is performed.

[0077] Preparation Example 1

[0078] 5 g of EDOT monomer was added to 100 mL of an ethanol solution, and magnetically stirred at room temperature for 30 min, and 1 g of p-toluenesulfonic acid was added to prepare an electrolyte solution.

[0079] A three-electrode system was used, the pretreated formation foil D1 was used as a working electrode, a platinum wire was used as a counter electrode, and a saturated calomel electrode was used as a reference electrode, the working electrode, the counter electrode and the reference electrode were immersed in the electrolyte solution, and an electrochemical polymerization reaction was performed at an oxidation potential of 1.6 V by a constant voltage method for 40 min, and then the working electrode was taken out, washed with deionized water, and dried at 80°C under vacuum for 20 min to obtain a high-density and high-stability conductive polymer film M1 based on electrochemical polymerization.

[0080] Preparation Example 2

[0081] A preparation method of a high-density and high-stability conductive polymer film based on electrochemical polymerization includes the following steps:

[0082] 10 g of EDOT monomer was added to 100 mL of a 50 wt% acetonitrile solution, and magnetically stirred at room temperature for 30 min, and 1 g of tetrabutylammonium hexafluorophosphate was added to prepare an electrolyte solution.

[0083] A three-electrode system was used, the pretreated formation foil D1 was used as a working electrode, a platinum wire was used as a counter electrode, and a saturated calomel electrode was used as a reference electrode, the working electrode, the counter electrode and the reference electrode were immersed in the electrolyte solution, and an electrochemical polymerization reaction was performed at an oxidation current of 0.1 mA by a constant current method for 60 min, and then the working electrode was taken out, washed with deionized water, and dried at 80°C under blowing air for 20 min to obtain a high-density and high-stability conductive polymer film M2 based on electrochemical polymerization.

[0084] Preparation Example 3

[0085] A preparation method of a high-density and high-stability conductive polymer film based on electrochemical polymerization includes the following steps:

[0086] 10g of EDOT monomer was added into 100 mL of ethanol mixed solution, and magnetically stirred at room temperature for 30 min, and 0.5g of p-toluenesulfonic acid was added to prepare an electrolyte;

[0087] A three-electrode system was used, the pretreated formation foil D1 was used as the working electrode, platinum wire was used as the counter electrode, and saturated calomel electrode was used as the reference electrode. The working electrode, the counter electrode and the reference electrode were immersed in the electrolyte, and the electrochemical polymerization reaction was carried out by cyclic voltammetry under the conditions of a voltage scanning range of 0-1.6V, a scanning rate of 50mV / s, and 50 cycles of cyclic scanning. After the reaction, the working electrode was taken out, washed with deionized water, and dried at 80℃ under blowing air for 20 min to obtain the high-density and high-stability conductive polymer film M3 based on electrochemical polymerization.

[0088] Preparation Example 4 was implemented

[0089] The preparation method of the high-density and high-stability conductive polymer film based on electrochemical polymerization includes the following steps:

[0090] 1.5g of EDOT monomer was added into 100 mL of ethanol: water blended solution (the volume ratio of ethanol to water was 75:25), and magnetically stirred at room temperature for 30 min, and p-toluenesulfonic acid was added to adjust the pH to 3 to prepare an electrolyte;

[0091] A three-electrode system was used, the pretreated formation foil D2 was used as the working electrode, platinum wire was used as the counter electrode, and saturated calomel electrode was used as the reference electrode. The working electrode, the counter electrode and the reference electrode were immersed in the electrolyte, and the electrochemical polymerization reaction was carried out by cyclic voltammetry under the conditions of a voltage scanning range of 0-1.6V, a scanning rate of 50mV / s, and 100 cycles of cyclic scanning. After the reaction, the working electrode was taken out, washed with deionized water, and dried at 80℃ under vacuum for 20 min to obtain the high-density and high-stability conductive polymer film M4 based on electrochemical polymerization.

[0092] Preparation Example 5 was implemented

[0093] The preparation method of the high-density and high-stability conductive polymer film based on electrochemical polymerization includes the following steps:

[0094] 1.5g of EDOT monomer was added into 100 mL of ethanol: water blended solution (the volume ratio of ethanol to water was 75:25), and magnetically stirred at room temperature for 30 min, and p-toluenesulfonic acid was added to adjust the pH to 3 to prepare an electrolyte;

[0095] The pretreated formation foil D2 is used as the working electrode, a platinum wire is used as the counter electrode, and a saturated calomel electrode is used as the reference electrode. The working electrode, the counter electrode, and the reference electrode are immersed in the electrolyte, and an electrochemical polymerization reaction is performed by cyclic voltammetry under the conditions of a voltage scanning range of 0-1.6 V, a scanning rate of 50 mV / s, and cyclic scanning for 80 cycles. After the reaction, the working electrode is taken out, washed with deionized water, and dried in a vacuum at 80°C for 20 min to obtain the high-compactness and high-stability conductive polymer film M5 based on electrochemical polymerization.

[0096] Preparation Example 6 is implemented

[0097] The preparation method of the high-compactness and high-stability conductive polymer film based on electrochemical polymerization includes the following steps:

[0098] 1.5 g of EDOT monomer is added to 100 mL of an ethanol:water blended solution (the volume ratio of ethanol to water is 75:25), and magnetic stirring is performed at room temperature for 30 min. p-Toluenesulfonic acid is added to adjust the pH to 3, and an electrolyte is prepared.

[0099] The pretreated formation foil D2 is used as the working electrode, a platinum wire is used as the counter electrode, and a saturated calomel electrode is used as the reference electrode. The working electrode, the counter electrode, and the reference electrode are immersed in the electrolyte, and an electrochemical polymerization reaction is performed by cyclic voltammetry under the conditions of a voltage scanning range of 0-1.6 V, a scanning rate of 50 mV / s, and cyclic scanning for 120 cycles. After the reaction, the working electrode is taken out, washed with deionized water, and dried in a vacuum at 80°C for 20 min.

[0100] After drying, the above step 1 is repeated once (i.e., a secondary electrochemical polymerization reaction is performed in the electrolyte again), and the high-compactness and high-stability conductive polymer film M6 based on electrochemical polymerization is obtained.

[0101] Preparation Example 7 is implemented

[0102] The preparation method of the high-compactness and high-stability conductive polymer film based on electrochemical polymerization includes the following steps:

[0103] 1.5 g of EDOT monomer is added to 100 mL of an ethanol:water blended solution (the volume ratio of ethanol to water is 75:25), and magnetic stirring is performed at room temperature for 30 min. p-Toluenesulfonic acid is added to adjust the pH to 3, and an electrolyte is prepared.

[0104] The pretreated formation foil D5 is used as a working electrode, a platinum wire is used as a counter electrode, and a saturated calomel electrode is used as a reference electrode in a three-electrode system. The working electrode, the counter electrode, and the reference electrode are immersed in an electrolyte to perform an electrochemical polymerization reaction by cyclic voltammetry under the conditions of a voltage scanning range of 0-1.6 V, a scanning rate of 50 mV / s, and 100 cycles of cyclic scanning. After the reaction, the working electrode is taken out, washed with deionized water, and dried at 80°C under vacuum for 20 min to obtain a high-density and high-stability conductive polymer film M7 based on electrochemical polymerization.

[0105] Test Example 1

[0106] The pretreated formation foils D1-D6 are subjected to SEM testing.

[0107] Test method: The test method known to those skilled in the relevant field is used, and the test instrument model is: Thermo Quattro S energy spectrum, EDAX ELECT PIUS.

[0108] The pretreated formation foils D1-D6 are immersed in conductive carbon paste on the surface, cured at room temperature, and then immersed in silver paste to prepare sheet-type laminated aluminum electrolytic capacitors A1-A6. The capacity extraction, equivalent series resistance (ESR), leakage current (LC), and high-temperature and high-humidity stability of the capacitors are tested.

[0109] Test method: The test method known to those skilled in the relevant field is used, and the test instrument model is: Zhisin Precision, ZX8516B-1X and ZX6589-800V.

[0110] The test results are shown in Figure 1 and Table 1, Figure 1 The SEM photos of the films prepared in Preparation Examples D1-D6 are shown, and the properties of the aluminum electrolytic capacitors A1-A6 based on the films prepared from D1-D6 are shown in Table 1.

[0111] Table 1: Performance test results of capacitors A1-A6

[0112]

[0113] Note: The capacitor ESR stability test is a high-temperature and high-humidity stability test, the environmental temperature is 85±2°C, the environmental relative humidity is 85±3% RH, and the duration is 1000 h.

[0114] From Figure 1 and Table 1, it can be seen that the pretreated formation foils of the present application have a relatively rough and non-dense morphology structure, and the prepared capacitors need to be improved in terms of capacity extraction rate, ESR, LC, and stability. However, the performance of the aluminum electrolytic capacitors A1-A5 prepared from the pretreated formation foils of the present application is significantly better than that of the aluminum electrolytic capacitor A6.

[0115] Test Example 2

[0116] SEM tests were performed on the conductive polymer films M1-M7.

[0117] Test method: The test method well known to those skilled in the relevant art was used, and the test instrument model was: Thermo Fisher Quattro S energy spectrum, EDAX ELECT PIUS.

[0118] The conductive polymer films M1-M7 based on electrochemical polymerization with high density and high stability were surface-coated with conductive carbon paste, and after room temperature curing, silver paste was coated to prepare sheet-type laminated aluminum electrolytic capacitors B1-B7. The capacity extraction, equivalent series resistance (ESR), leakage current (LC), and high temperature and high humidity stability of the capacitors were tested.

[0119] Test method: The test method well known to those skilled in the relevant art was used, and the test instrument model was: Zhisin Precision, ZX8516B-1X and ZX6589-800V.

[0120] The test results are shown in Figure 2 and Table 2, Figure 2 The SEM photos of the films prepared in the preparation examples M1-M7 are shown, and the properties of the aluminum electrolytic capacitors B1-B7 based on the preparation examples are shown in Table 2.

[0121] Table 2: Test results of the properties of the capacitors B1-B8

[0122]

[0123] Note: The capacitor ESR stability test is a high temperature and high humidity stability test, the environmental temperature is 85±2℃, the environmental relative humidity is 85±3% RH, and the duration is 1000h.

[0124] From Figure 2 and Table 2, it can be concluded that the films based on the preparation examples of the present application have a flat and dense morphology structure, and the prepared capacitors have higher capacity extraction rate, lower ESR, higher ESR stability, and lower leakage current. Compared with the test results in Table 1, the performance and stability of the aluminum electrolytic capacitors prepared based on the method described in the present application have been comprehensively improved.

[0125] It will be obvious to a person skilled in the art that the application is not limited to the details of the above-described exemplary embodiments, but that the application can be implemented in other embodiments without departing from the scope of the application. The embodiments are therefore to be seen as exemplary and in no way restrictive, the scope of the application being defined by the claims below rather than by the above description, and all variations falling within the meaning and range of equivalency of the essential characteristics of the claims are therefore intended to be embraced therein.

[0126] Furthermore, it should be understood that although the description is made according to embodiments, not every embodiment contains only one independent technical solution, and the description is made in this way only for the sake of clarity, and a person skilled in the art should consider the description as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by a person skilled in the art.

Claims

1. A method for producing a high-density and high-stability conductive polymer thin film based on electrochemical polymerization, characterized by, The method comprises the following steps: The working electrode is obtained by pretreating the formed foil with a treatment solution, and then the working electrode, the reference electrode and the counter electrode are immersed in an electrolyte to perform electrochemical polymerization through a three-electrode system to obtain the high-density and high-stability conductive polymer film based on electrochemical polymerization; The treatment solution is selected from an oxidant solution and a BFDO monomer solution; The treatment solution is selected from a PBFDO solution; The pretreatment comprises the following steps: The formed foil is immersed in the PBFDO solution, dried, and repeated for several times to obtain the pretreated formed foil; The formed foil is immersed in the oxidant solution, dried, and then immersed in the BFDO monomer solution, dried, and repeated for several times to obtain the pretreated formed foil; The formed foil is immersed in the BFDO monomer solution, dried, and then immersed in the oxidant solution, dried, and repeated for several times to obtain the pretreated formed foil; The electrolyte is selected from a solution containing an EDOT monomer and derivatives thereof; The concentration of the solution is 5-300 mg / mL.

2. The method for preparing the high-density and high-stability conductive polymer film based on electrochemical polymerization according to claim 1, wherein the formed foil is immersed in the PBFDO solution for 4-20 s; The formed foil is immersed in the oxidant solution for 4-20 s; The formed foil is immersed in the BFDO monomer solution for 4-20 s. The oxidant is selected from one or more of a metal salt oxidant, an oxide, a peroxide, a quinone compound and an acid anhydride compound.

4. The method for preparing the high-density and high-stability conductive polymer film based on electrochemical polymerization according to claim 1, wherein the method for electrochemical oxidation polymerization adopts one of a constant voltage method, a constant current method and a cyclic voltammetry method; The oxidation potential is 0.3-3.0 V, and the oxidation polymerization time is 5-200 min in the constant voltage method; The oxidation current is 0.1 μA-10 mA, and the oxidation polymerization time is 5-200 min in the constant current method; The voltage scanning range is -1.0-3.0 V, the scanning rate is 20-100 mV / s, and the number of cycles is 10-5000 times in the cyclic voltammetry method.

3. The method of claim 1, wherein the electrochemical polymerization is carried out in a solution of an electrolyte and a monomer. The three-electrode system comprises a working electrode, a counter electrode and a reference electrode; The working electrode is selected from the pretreated formed foil; The counter electrode is selected from one or more of a platinum electrode and a graphite electrode; The reference electrode is selected from one or more of a saturated calomel electrode, a silver chloride electrode and a mercury / mercurous sulfate electrode.

6. The high-density and high-stability conductive polymer film based on electrochemical polymerization prepared by the method of any one of claims 1-5 is applied in the field of supercapacitors and electrolytic capacitors. ​ ​ 5. The method of claim 1, wherein the electrochemical polymerization is carried out in a solution of an electrolyte and a monomer. ​ ​ ​ ​ ​

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