阅读说明：本技术 低阻抗固液混合电解液及其制备方法与应用 (Low-impedance solid-liquid mixed electrolyte and preparation method and application thereof ) 是由 潘登 吉泽锋 刘平 苏秀娟 杨阳 于 2021-07-16 设计创作，主要内容包括：本发明属于电解液技术领域,公开了一种低阻抗固液混合电解液及其制备方法与应用。所述固液混合电解液,包含PEDOT/PSS聚合物,制备所述PEDOT/PSS聚合物的操作包括分步聚合和超声搅拌。所述低阻抗固液混合电解液的性能优良,采用所述低阻抗固液混合电解液所制得的电容器具备更好的容量引出率、耐高温性能和导电性能。(The invention belongs to the technical field of electrolyte, and discloses low-impedance solid-liquid mixed electrolyte and a preparation method and application thereof. The solid-liquid mixed electrolyte contains PEDOT/PSS polymer, and the operation of preparing the PEDOT/PSS polymer comprises step-by-step polymerization and ultrasonic stirring. The low-impedance solid-liquid mixed electrolyte has excellent performance, and a capacitor prepared from the low-impedance solid-liquid mixed electrolyte has better capacity extraction rate, high temperature resistance and conductivity.)

1. A low-impedance solid-liquid mixed electrolyte is characterized by comprising PEDOT/PSS polymer, and the operation of preparing the PEDOT/PSS polymer comprises step-by-step polymerization and ultrasonic stirring.

2. The low impedance solid liquid mixed electrolyte of claim 1 wherein the PEDOT/PSS polymer is present in the low impedance solid liquid mixed electrolyte in an amount of 6-12% by weight.

3. The low impedance solid liquid mixed electrolyte of claim 1 further comprising a permeation-assisting solvent comprising at least one of ethylene glycol, sulfolane or γ -butyrolactone.

4. The low impedance solid-liquid mixed electrolyte of claim 3 wherein the permeation assisting solvent is a combination of ethylene glycol, sulfolane and γ -butyrolactone.

5. The low impedance solid liquid mixed electrolyte of claim 3 further comprising a high temperature stabilizer comprising at least one of boric acid, salicylic acid or p-nitrophenol.

6. The method for preparing a low impedance solid-liquid mixed electrolyte of claim 5, comprising the steps of:

(1) mixing water, 3, 4-ethylenedioxythiophene and a catalyst, adding sodium polystyrene sulfonate step by step for multiple times to react, and performing ultrasonic stirring to prepare a PEDOT/PSS dispersion liquid;

(2) and mixing a penetration assisting solvent and a high-temperature stabilizer with the PEDOT/PSS dispersion liquid to prepare the low-impedance solid-liquid mixed electrolyte.

7. The preparation method according to claim 5, wherein the number of times of the stepwise multiple addition in step (1) is not less than 3.

8. The method according to claim 5, wherein the PEDOT/PSS dispersion of step (1) further comprises at least one of sulfuric acid, polyethylene glycol or isopropanol.

9. The method according to claim 5, wherein the step (1) and/or the step (2) further comprises a heating operation.

10. Use of the low impedance solid liquid mixed electrolyte of any one of claims 1 to 5 in the manufacture of a capacitor.

Technical Field

The invention belongs to the technical field of electrolyte, and particularly relates to low-impedance solid-liquid mixed electrolyte and a preparation method and application thereof.

Background

At the present stage, the technology of using conductive polymer polythiophene as cathode material greatly promotes the technical development of aluminum electrolytic capacitor. Compared with the traditional liquid aluminum electrolytic capacitor, the conductive polymer solid aluminum electrolytic capacitor has great advantages in the aspects of low-temperature performance and high-frequency characteristic, can adapt to the application of high-power, high-frequency and large-ripple filtering, but also has the problems of larger electric leakage, poorer surge voltage resistance and the like. The aluminum electrolytic capacitor prepared by adopting the solid-liquid mixed electrolyte can better combine the advantages of a solid state and a liquid state, so that the application in the industries of new energy automobiles, 5G communication, high-power quick charging, industrial frequency converters and the like is rapidly developed.

However, the conventional solid-liquid mixed electrolyte (electrolyte) has certain disadvantages in terms of high-temperature stability, capacity extraction rate, conductivity and other properties. Therefore, it is desirable to provide a solid-liquid mixed electrolyte product with better combination property and simpler production.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art described above. Therefore, the invention provides the low-impedance solid-liquid mixed electrolyte and the preparation method and application thereof, the low-impedance solid-liquid mixed electrolyte has excellent performance, and the capacitor prepared by adopting the low-impedance solid-liquid mixed electrolyte has better capacity extraction rate, high temperature resistance and conductivity.

The invention provides a low-impedance solid-liquid mixed electrolyte, which comprises PEDOT/PSS polymer, and the operation of preparing the PEDOT/PSS polymer comprises step-by-step polymerization and ultrasonic stirring.

When the electrolyte is used for preparing the aluminum electrolytic capacitor, the electrolyte and the polythiophene component contained in the electrolyte need to enter holes of the aluminum foil, so that certain requirements are imposed on the particle size of the polythiophene, and the effect is better when the particle size is smaller. However, when the polythiophene is prepared using a high-concentration raw material, it is difficult to ensure the particle size and stability of the product, and the low-concentration raw material may adversely affect the conductivity of the prepared product, so that the particle size of the polythiophene in the conventional electrolyte is generally varied from 40 nm to several hundreds of nm, and it is difficult to realize a smaller particle size. The invention discloses a preparation method of a PEDOT/PSS polymer, which belongs to one of polythiophene, and the preparation method is characterized in that the particle size of most of the PEDOT/PSS polymer prepared by adopting a mode of step-by-step polymerization and ultrasonic stirring is smaller than 30nm, so that the particle size of the PEDOT/PSS polymer can be effectively reduced.

Preferably, the PEDOT/PSS polymer accounts for 6-12% by mass of the low-impedance solid-liquid mixed electrolyte. The PEDOT/PSS polymer content in the low-impedance solid-liquid mixed electrolyte is high, and good conductivity can be realized.

Preferably, the low-impedance solid-liquid mixed electrolyte further comprises a permeation-assisting solvent, and the permeation-assisting solvent comprises at least one of ethylene glycol, sulfolane or gamma-butyrolactone. The ethylene glycol, the sulfolane and the gamma-butyrolactone not only play a role of a solvent, but also can improve the permeability and the capacity extraction of the electrolyte.

More preferably, the pro-osmotic solvent is a combination of ethylene glycol, sulfolane and gamma-butyrolactone. Because the ethylene glycol has higher viscosity, the sulfolane, the gamma-butyrolactone and the ethylene glycol are matched, so that the viscosity can be effectively controlled, and better electrolyte permeability and capacity extraction improvement effects can be realized.

Preferably, the low-impedance solid-liquid mixed electrolyte further comprises a high-temperature stabilizer, wherein the high-temperature stabilizer is a combination of boric acid, salicylic acid and p-nitrophenol.

The invention also provides a preparation method of the low-impedance solid-liquid mixed electrolyte, which comprises the following steps:

(1) mixing water, 3, 4-ethylenedioxythiophene and a catalyst, adding sodium polystyrene sulfonate step by step for multiple times to react, and performing ultrasonic stirring to prepare a PEDOT/PSS dispersion liquid;

(2) and mixing a penetration assisting solvent and a high-temperature stabilizer with the PEDOT/PSS dispersion liquid to prepare the low-impedance solid-liquid mixed electrolyte.

The PEDOT/PSS dispersion liquid in the step (1) contains the prepared PEDOT/PSS polymer, and the majority of the PEDOT/PSS polymer has the particle size of less than 30 nm.

Preferably, the catalyst is at least one of sodium persulfate, ammonium persulfate, or hydrogen peroxide.

Preferably, the times of the step-by-step multiple addition in the step (1) are more than or equal to 3 times. Tests show that when the times of adding the PEDOT/PSS polymer step by step for multiple times are more than or equal to 3 times, the PEDOT/PSS polymer with smaller particle size can be prepared.

Preferably, the PEDOT/PSS dispersion of step (1) further comprises sulfuric acid. Sulfuric acid prevents Na ions from destroying the polymerization reaction.

Preferably, the PEDOT/PSS dispersion liquid in the step (1) also comprises polyethylene glycol. Polyethylene glycol can reduce the ESR (equivalent series resistance) value of PEDOT/PSS polymer, and is helpful for improving the performance of the PEDOT/PSS polymer.

Preferably, the PEDOT/PSS dispersion of step (1) further comprises isopropanol. Isopropanol improves the viscosity, prevents evaporation and stabilizes the PEDOT/PSS dispersion.

Preferably, the step (1) includes a heating operation.

Preferably, the step (2) includes a heating operation.

The heating operation can promote the reaction and the mixing of the raw materials, and can also remove excessive water in the solid-liquid mixed electrolyte.

The invention also provides application of the low-impedance solid-liquid mixed electrolyte in preparation of a capacitor.

Compared with the prior art, the invention has the following beneficial effects:

according to the invention, the mode of step-by-step polymerization and ultrasonic stirring is adopted, so that the particle size of most of the prepared PEDOT/PSS polymer can be smaller than 30nm, the particle size of the PEDOT/PSS can be effectively reduced, and the performance of the solid-liquid mixed electrolyte is improved. Meanwhile, the invention also adds the permeation-assistant solvent (ethylene glycol, sulfolane and gamma-butyrolactone) and the high-temperature stabilizer (boric acid, salicylic acid and p-nitrophenol) into the low-impedance solid-liquid mixed electrolyte, thereby further improving the capacity extraction rate, the high-temperature stability, the conductivity and other properties.

Detailed Description

In order to make the technical solutions of the present invention more apparent to those skilled in the art, the following examples are given for illustration. It should be noted that the following examples are only preferred embodiments of the present invention, and the claimed protection scope is not limited thereto, and any modification, substitution, combination made without departing from the spirit and principle of the present invention are included in the protection scope of the present invention.

The starting materials, reagents or apparatuses used in the following examples are conventionally commercially available or can be obtained by conventionally known methods, unless otherwise specified.

Example 1

The embodiment provides a low-impedance solid-liquid mixed electrolyte which comprises the following components in percentage by weight: 8% of PEDOT/PSS polymer, 2% of sodium persulfate, 1% of sulfuric acid, 2% of polyethylene glycol, 1% of isopropanol, 20% of sulfolane, 10% of gamma-butyrolactone, 0.5% of p-nitrophenol, 0.5% of boric acid, 2% of salicylic acid and the balance of ethylene glycol.

The preparation method of the low-impedance solid-liquid mixed electrolyte in the embodiment comprises the following steps:

(1) adding 3, 4-ethylenedioxythiophene and sodium persulfate into water, adding one third of total polystyrene sodium sulfonate, heating to 50 ℃, and mechanically stirring for 10 min; cooling to room temperature, adding sulfuric acid, polyethylene glycol and isopropanol, one third of total polystyrene sodium sulfonate, heating to 50 deg.C, and ultrasonically stirring for 10 min; finally, adding the rest sodium polystyrene sulfonate, and ultrasonically stirring for 20min to prepare PEDOT/PSS dispersion liquid;

(2) adding sulfolane into PEDOT/PSS dispersion, heating to 90 ℃, and adding gamma-butyrolactone and part of ethylene glycol after 30 min; and (3) continuously heating for 30min, adding p-nitrophenol, boric acid, salicylic acid and residual glycol, and continuously heating until the water content in the system is less than 0.5% to prepare the low-impedance solid-liquid mixed electrolyte.

Example 2

The embodiment provides a low-impedance solid-liquid mixed electrolyte which comprises the following components in percentage by weight: 8% of PEDOT/PSS polymer, 3% of sodium persulfate, 1% of sulfuric acid, 1.5% of polyethylene glycol, 1% of isopropanol, 15% of sulfolane, 15% of gamma-butyrolactone, 0.5% of p-nitrophenol, 0.5% of boric acid, 2% of salicylic acid and the balance of ethylene glycol.

The preparation method of the low-impedance solid-liquid mixed electrolyte in the embodiment comprises the following steps:

(1) adding 3, 4-ethylenedioxythiophene and sodium persulfate into water, adding one third of total polystyrene sodium sulfonate, heating to 55 ℃, and ultrasonically stirring for 15 min; cooling to room temperature, adding sulfuric acid, polyethylene glycol and isopropanol, one third of total polystyrene sodium sulfonate, heating to 50 deg.C, and ultrasonically stirring for 10 min; finally, adding the rest sodium polystyrene sulfonate, and ultrasonically stirring for 20min to prepare PEDOT/PSS dispersion liquid;

(2) adding sulfolane into PEDOT/PSS dispersion, heating to 85 ℃, and adding gamma-butyrolactone and part of ethylene glycol after 35 min; and (3) continuously heating for 30min, adding p-nitrophenol, boric acid, salicylic acid and residual glycol, and continuously heating until the water content in the system is less than 0.5% to prepare the low-impedance solid-liquid mixed electrolyte.

Example 3

The embodiment provides a low-impedance solid-liquid mixed electrolyte which comprises the following components in percentage by weight: 8% of PEDOT/PSS polymer, 2% of sodium persulfate, 1% of sulfuric acid, 2% of polyethylene glycol, 1% of isopropanol, 0.5% of p-nitrophenol, 0.5% of boric acid, 2% of salicylic acid and the balance of ethylene glycol.

The preparation method of the low-impedance solid-liquid mixed electrolyte in the embodiment comprises the following steps:

(1) adding 3, 4-ethylenedioxythiophene and sodium persulfate into water, adding one third of total polystyrene sodium sulfonate, heating to 50 ℃, and mechanically stirring for 10 min; cooling to room temperature, adding sulfuric acid, polyethylene glycol and isopropanol, one third of total polystyrene sodium sulfonate, heating to 50 deg.C, and ultrasonically stirring for 10 min; finally, adding the rest sodium polystyrene sulfonate, and ultrasonically stirring for 20min to prepare PEDOT/PSS dispersion liquid;

(2) adding p-nitrophenol, boric acid, salicylic acid and residual glycol into PEDOT/PSS dispersion liquid, heating to 90 ℃, and continuously heating until the water content in the system is less than 0.5 percent to prepare the low-impedance solid-liquid mixed electrolyte.

Compared with example 1, the low-resistivity solid-liquid mixed electrolyte in example 3 does not contain sulfolane and gamma-butyrolactone.

Example 4

The embodiment provides a low-impedance solid-liquid mixed electrolyte which comprises the following components in percentage by weight: 8% of PEDOT/PSS polymer, 2% of sodium persulfate, 1% of sulfuric acid, 2% of polyethylene glycol, 1% of isopropanol, 20% of sulfolane, 10% of gamma-butyrolactone, 3% of adipic acid and the balance of ethylene glycol.

The preparation method of the low-impedance solid-liquid mixed electrolyte in the embodiment comprises the following steps:

(1) adding 3, 4-ethylenedioxythiophene and sodium persulfate into water, adding one third of total polystyrene sodium sulfonate, heating to 50 ℃, and mechanically stirring for 10 min; cooling to room temperature, adding sulfuric acid, polyethylene glycol and isopropanol, one third of total polystyrene sodium sulfonate, heating to 50 deg.C, and ultrasonically stirring for 10 min; finally, adding the rest sodium polystyrene sulfonate, and ultrasonically stirring for 20min to prepare PEDOT/PSS dispersion liquid;

(2) adding sulfolane into PEDOT/PSS dispersion, heating to 90 ℃, and adding gamma-butyrolactone and part of ethylene glycol after 30 min; and (3) after continuously heating for 30min, adding adipic acid and the residual glycol, and continuously heating until the water content in the system is less than 0.5% to prepare the low-impedance solid-liquid mixed electrolyte.

Compared with the embodiment 1, in the embodiment 4, the low-resistance solid-liquid mixed electrolyte is prepared by replacing p-nitrophenol, boric acid and salicylic acid with adipic acid.

Comparative example 1

The comparative example provides a solid-liquid mixed electrolyte, which comprises the following components in percentage by weight: 8% of PEDOT/PSS polymer, 2% of sodium persulfate, 1% of sulfuric acid, 2% of polyethylene glycol, 1% of isopropanol, 20% of sulfolane, 10% of gamma-butyrolactone, 0.5% of p-nitrophenol, 0.5% of boric acid, 2% of salicylic acid and the balance of ethylene glycol.

The preparation method of the solid-liquid mixed electrolyte in the comparative example comprises the following steps:

(1) adding 3, 4-ethylenedioxythiophene and sodium persulfate into water, adding sulfuric acid, polyethylene glycol, isopropanol and sodium polystyrene sulfonate, heating to 50 ℃, and ultrasonically stirring for 40min to prepare PEDOT/PSS dispersion;

(2) adding sulfolane into PEDOT/PSS dispersion, heating to 90 ℃, and adding gamma-butyrolactone and part of ethylene glycol after 30 min; and continuously heating for 30min, adding p-nitrophenol, boric acid, salicylic acid and residual glycol, and continuously heating until the water content in the system is less than 0.5% to obtain the solid-liquid mixed electrolyte.

In contrast to example 1, one-step polymerization was used instead of stepwise polymerization in comparative example 1.

Comparative example 2

The comparative example provides a solid-liquid mixed electrolyte, which comprises the following components in percentage by weight: 8% of PEDOT/PSS polymer, 2% of sodium persulfate, 1% of sulfuric acid, 2% of polyethylene glycol, 1% of isopropanol, 20% of sulfolane, 10% of gamma-butyrolactone, 0.5% of p-nitrophenol, 0.5% of boric acid, 2% of salicylic acid and the balance of ethylene glycol.

The preparation method of the solid-liquid mixed electrolyte in the comparative example comprises the following steps:

(1) adding 3, 4-ethylenedioxythiophene and sodium persulfate into water, adding one third of total polystyrene sodium sulfonate, heating to 50 ℃, and mechanically stirring for 10 min; cooling to room temperature, adding sulfuric acid, polyethylene glycol and isopropanol, one third of total polystyrene sodium sulfonate, heating to 50 deg.C, and mechanically stirring for 10 min; finally, adding the rest sodium polystyrene sulfonate, and mechanically stirring for 20min to prepare PEDOT/PSS dispersion liquid;

(2) adding sulfolane into PEDOT/PSS dispersion, heating to 90 ℃, and adding gamma-butyrolactone and part of ethylene glycol after 30 min; and continuously heating for 30min, adding p-nitrophenol, boric acid, salicylic acid and residual glycol, and continuously heating until the water content in the system is less than 0.5% to obtain the solid-liquid mixed electrolyte.

In contrast to example 1, mechanical agitation was used instead of ultrasonic agitation in comparative example 2.

Product effectiveness testing

According to detection, the particle size of more than 70-80% of PEDOT/PSS polymer in the solid-liquid mixed electrolyte prepared in the embodiment 1-4 is less than 30nm, the particle size range of the PEDOT/PSS polymer in the solid-liquid mixed electrolyte prepared in the comparative example 1 is 60-180nm, and the particle size range of the PEDOT/PSS polymer in the solid-liquid mixed electrolyte prepared in the comparative example 2 is 50-150 nm.

The solid-liquid mixed electrolyte prepared in the examples 1 to 4 and the comparative examples 1 to 2 is respectively impregnated by the same core cladding, so as to prepare corresponding capacitor products (sequentially named as capacitors 1 to 6), wherein the specific preparation method of the capacitor is as follows:

(1) winding the positive aluminum foil, the negative carbon foil, the positive and negative guide pins and the electrolytic paper into a core bag,

(2) spot welding the core cladding on the iron bar for formation charging,

(3) drying the formed core bag and impregnating the core bag with the electrolyte,

(4) and (3) packaging the core bag impregnated with the electrolyte by using butyl rubber and an aluminum shell to obtain the capacitor (specification: 35V 390; size: 10X 12.5).

The performance of the capacitor products (capacitors 1-6) thus produced was tested and the test results are shown in Table 1.

TABLE 1 capacitive Performance test results

The present invention is not limited to the above-described embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those skilled in the art. Furthermore, the embodiments and features of the embodiments of the present application may be combined with each other without conflict.