WO2017143737A1

WO2017143737A1 - Aluminum electrolytic capacitor and manufacturing method thereof

Info

Publication number: WO2017143737A1
Application number: PCT/CN2016/094922
Authority: WO
Inventors: 赵大成; 李付亚
Original assignee: 深圳新宙邦科技股份有限公司
Priority date: 2016-02-25
Filing date: 2016-08-12
Publication date: 2017-08-31
Also published as: CN105761937B; CN105761937A

Abstract

An aluminum electrolytic capacitor and a manufacturing method thereof. An oxidation potential of an anode of the aluminum electrolytic capacitor exceeds 30V and comprises dispersion comprising an electrically conducting polymer and a dispersant. The electrically conducting polymer has an average particle size of 10-30nm. The aluminum electrolytic capacitor has the advantages of easy manufacturing, low loss, low equivalent series resistance, and low leakage current.

Description

Aluminum electrolytic capacitor and preparation method thereof

Technical field

The present application relates to the field of capacitors, and in particular to an aluminum electrolytic capacitor and a method of manufacturing the same.

Background technique

The conductive polymer is a kind of polymer compound having a conjugated π bond structure, which is chemically or electrochemically doped to form an anion or a cation to form a conductive special polymer material, including polyacetylene, polythiophene, polypyrrole. , polyaniline, polyparaphenylene, polycarbazole and polyfluorene. The outstanding advantages of conductive polymers are that they have both the photoelectric properties of metal and semiconductor materials, good polymer stability and mechanical properties, relatively light weight, and ease of processing. The most successful conductive polymers currently used in the industrial field are polyaniline and polythiophene, especially poly(3,4-ethylenedioxythiophene) (PEDOT) among polythiophene derivatives, but also because of its high conductivity, Good environmental stability, transparency in doped state, etc., and widely used in electronic devices such as organic electro-display, organic solar cells and supercapacitors.

Since the discovery of conductive polymers, products prepared by electrochemical methods or chemical methods are generally poorly soluble conductive polymer powders, which are difficult to process, thus greatly limiting their applications. Until the 1980s, Bayer introduced poly(p-styrenesulfonic acid (PSS) as a charge-balancing dopant in the chemical oxidative polymerization of 3,4-ethylenedioxythiophene (EDOT) to prepare poly(3, 4-ethylenedioxythiophene)/polystyrenesulfonic acid (PEDOT/PSS), which has excellent water dispersion properties, coating film forming properties, high electrical conductivity, optical transparency, environmental stability, etc. Used in supercapacitors, antistatic coatings, anti-corrosion coatings, electroluminescent materials, sensors, conductive inks and other fields.

The Chinese invention patent No. 200680033112.0 discloses a method for preparing an electrolytic capacitor, the method comprising at least the following steps: a) subjecting the porous electrode body (2) of the electrode material to anodization to form a dielectric covering the surface of the electrode material. (3); b) applying a dispersion A) on the porous body, the porous body comprising at least the porous electrode body (2) of the electrode material and the dielectric (3), the dispersion A) containing at least particles of the conductive polymer B) and dispersed Agent D); c) for forming a solid electrolyte (4) completely or partially covering the surface of the dielectric, at least partially removing and/or curing the dispersant D), the maximum anodization voltage of the porous electrode body (2) during anodization is greater than At 30 V, the conductive polymer particles B) in the dispersion A) have an average particle diameter of from 1 to 100 nm. That is, the applied conductive particles have an average particle diameter of 1-100 nm and an anodization voltage of more than 30V. It has been found through testing that the electrolytic capacitor of the above invention still has problems in that the capacity and loss, the equivalent series resistance, and the leakage performance cannot be balanced.

Summary of the invention

The technical problem to be solved by the present invention is to provide an aluminum electrolytic capacitor which can control a suitable molecular weight, which is easy to discharge, low in loss, low in equivalent series resistance, and low in leakage, and further provides a method for preparing the above aluminum electrolytic capacitor.

In order to solve the above technical problems, the technical solution adopted by the present invention is:

An aluminum electrolytic capacitor having an oxidation voltage of an anode of the aluminum electrolytic capacitor of more than 30 V, comprising a dispersion comprising a conductive polymer and a dispersant, the conductive polymer having an average particle diameter of 10 to 30 nm.

The present invention also provides a method of preparing an aluminum electrolytic capacitor, the dispersion is applied to an electrode of the above-described aluminum electrolytic capacitor, and then the dispersant is partially or completely removed, or the dispersant is cured. The number of removals or curings is one or more times.

The beneficial effects of the invention are:

(1) When the oxidation voltage of the anode is greater than 30 V and the pore diameter is large, the design of controlling the average particle diameter of the conductive polymer is 10-30 nm, and the technical effect of easy discharge is achieved;

(2) The obtained aluminum electrolytic capacitor has the advantages of low loss, low equivalent series resistance, and low leakage.

Detailed ways

The details of the technical contents, the objects and effects achieved by the present invention will be described below in conjunction with the embodiments.

The most critical idea of the present invention is that, by controlling the average particle diameter of the conductive polymer to be 10-30 nm under the condition that the anodization voltage is greater than 30 V, the technical effect of easy discharge is achieved.

The present invention provides an aluminum electrolytic capacitor having an anodic oxidation voltage of more than 30 V, comprising a dispersion comprising a conductive polymer and a dispersant, the conductive polymer having an average particle diameter of 10 30nm.

The technical idea of the present invention is:

It is known that the relationship between the capacitor voltage and the discharge capacity is such that as the voltage increases, the pore size of the porous anode becomes larger, and the lower the voltage, the smaller the pore size, and the more difficult the discharge will be.

When the molecular weight is smaller, the particle size is smaller, but the stability and electrical conductivity are deteriorated. Therefore, when the particle diameter is 1-10 nm, the particle diameter is too small, and the conductivity of the dispersion is low, and the prepared capacitor is obtained. The equivalent series resistance will become larger; when the molecular weight is large, the particle size is large, the stability is good, and the conductivity is superior, but the molecular weight is too large, and the particle size is too large, which is unfavorable for entering the pores of the porous anode; Thus when the particle size is 30-100nm, because the particle size is too large, is not conducive to the dispersion into the pores of the electrode, the capacitor obtained by the preparation has a low capacity and high loss. Therefore, the prior art electrolytic capacitor has a problem that the capacity, the loss performance, the equivalent series resistance, and the electrical conductivity (such as leakage performance) cannot be balanced.

The applicant based on the above problems found that when the oxidation voltage of the anode is greater than 30V, the particle size of the conductive particles is controlled to be between 10-30 nm, and the PEDOT/PSS dispersion is sheared, and the particle size and aggregation after homogenization. The molecular weight of styrene sulfonic acid (pss) is closely related; considering the stability, conductivity and particle size of the dispersion, and through long-term experiments, the oxidation voltage at the anode is greater than 30V, and the average particle size of the conductive polymer is controlled. It is 10-30nm. At this time, the combination of pore size and particle size can achieve the technical effect of high capacity. At the same time, when the voltage is greater than 30V, the pore size is larger, the dispersion is easy to enter the hole, and the hole enters. The more the dispersion, the better the performance of the capacitor produced, so the obtained aluminum electrolytic capacitor has the advantages of low loss, low equivalent series resistance, and low leakage.

As can be seen from the above description, the beneficial effects of the present invention are:

Further, the conductive polymer comprises a polythiophene derivative, and the polythiophene derivative comprises a repeating unit having the composition of the following formula I and/or formula II, wherein the formula of the formula I is:

The structural formula of the general formula II is:

In the structural formula of the formula I and the formula of the formula II, A is an optionally substituted alkylene group having 1 to 5 carbon atoms; R is an optionally substituted direct bond having 5 to 12 carbon atoms or A branched cycloalkyl group, an optionally substituted straight or branched aryl group having 6 to 14 carbon atoms, an optionally substituted linear or branched aralkyl group having 7 to 18 carbon atoms, optionally substituted A linear or branched hydroxyalkyl group having a carbon number of 1 to 4 or a hydroxyl group; and X is an integer of 0-8.

Where A binds to several A groups, these groups may be the same or different.

The polythiophene derivative of the present invention may be a repeating unit having a composition of the formula I, a repeating unit having a composition of the formula II, or a repeating unit having a composition of the formula I and the formula II.

As apparent from the above description, the polythiophene derivative may be an optionally substituted polythiophene, and preferably the above-mentioned repeating unit having a composition of the following formula I and/or formula II. The polythiophene derivative of the above structure can be better matched with the pore size of the anode to further improve the ease of discharge.

Further, the conductive polymer further includes at least one of a polypyrrole derivative and a polyaniline derivative.

Further, the dispersion further comprises a polymeric anion. Preferably, the polymeric anion is a polymeric carboxylic acid anion or a polymeric sulfonate anion. More preferably, the polymeric anion is a polystyrene sulfonate anion having a molecular weight of from 2,000 to 500,000.

It can be seen from the above description that a polymeric anion is added to the dispersion, and the polyanion can be used as a composite ion, which is complexed with polythiophene and then dispersed in water. The polyanion can also act as a dopant to control the molecular weight of the polystyrene sulfonate anion to 2000- 500000, the polythiophene can be better dispersed in water. Among them, more preferably, the polystyrenesulfonate anion has a molecular weight of 10,000 to 200,000.

Further, the dispersing agent is an organic solvent and/or water.

Further, the dispersion further includes at least one of a crosslinking agent, a surfactant, and an additive selected from the group consisting of an ether, a lactone, an amide group, a lactam group, a sulfone, a sulfoxide, a sugar, At least one of a sugar derivative, a sugar alcohol, a furan derivative, a glycol, and a polyol.

As can be seen from the above description, the crosslinking agent and the surfactant may be those commonly used in the prior art as crosslinking agents and surfactants. The addition of the crosslinking agent, the surfactant and the additive respectively have an effect of effectively crosslinking and lowering the surface tension.

Further, the dispersion has a pH of 1.5-7, and the dispersion has a viscosity of not more than 500 cps at 20 °C.

From the above description, it is understood that the pH and viscosity of the dispersion can be controlled as described above. More preferably, the pH of the dispersion is 2 to 5, and the viscosity can be tested at 60 rpm.

In the method of preparing the aluminum electrolytic capacitor of the present invention:

The pH in the dispersion can be adjusted by adding an acid or a base; the step of "applying the dispersion and then partially or completely removing the dispersant or curing the dispersant" can be carried out once or repeatedly. More than two times.

Further, the design of the synthesis of the dispersion of the present invention and the screening of the composition of the dispersion raw material can sufficiently take into consideration the stability, conductivity and particle diameter of the dispersion to obtain good properties (easier capacity, low loss, etc.) Low series resistance and low leakage).

Example 1

An aluminum electrolytic capacitor of the embodiment, wherein an anode of the aluminum electrolytic capacitor has an oxidation voltage of 30 V, and includes a dispersion comprising a conductive polymer, a dispersant, and a polymeric anion, and further comprising an additive, wherein the additive is A mixture of an ether, a lactone, an amide group, a furan derivative, and a polyol. The dispersion had a pH of 1.5 and the dispersion had a viscosity of 500 cps at 20 °C. The conductive polymer had an average particle diameter of 10 nm. The conductive polymer includes a polythiophene derivative, and further includes a polypyrrole derivative. The polymeric anion is a polystyrene sulfonate anion, the polystyrene sulfonate anion has a molecular weight of 2000, and the dispersing agent is water. The polythiophene derivative includes a repeating unit having the composition of the following formula I, and the structural formula of the formula I is:

In the formula of the formula I, A is an optionally substituted alkylene group having 1 carbon atom; R is an optionally substituted straight or branched cycloalkyl group having 5 carbon atoms, optionally substituted a linear aryl group having 6 carbon atoms, an optionally substituted linear aralkyl group having 7 carbon atoms, an optionally substituted linear hydroxyalkyl group having 1 carbon atom or a hydroxyl group; and X is 0.

Example 2

An aluminum electrolytic capacitor of the embodiment, wherein an anode of the aluminum electrolytic capacitor has an oxidation voltage of 50 V, and comprises a dispersion comprising a conductive polymer, a dispersant, and a polymeric anion, and further comprising an additive, wherein the additive is ether. The pH of the dispersion was 7, and the viscosity of the dispersion at 20 ° C was 400 cps. The conductive polymer had an average particle diameter of 30 nm. The conductive polymer includes a polythiophene derivative, and further includes a polypyrrole derivative and a polyaniline derivative. The polymeric anion is a polystyrene sulfonate anion, the polystyrene sulfonate anion has a molecular weight of 500,000, and the dispersing agent is an organic solvent. The polythiophene derivative includes a repeating unit having the composition of the following formula II, and the structural formula of the formula II is:

In the structural formula of the formula II, A is an optionally substituted alkylene group having 5 carbon atoms; R is an optionally substituted branched cycloalkyl group having 12 carbon atoms, optionally substituted carbon atoms Is a branched aryl group of 14, an optionally substituted branched aralkyl group having 18 carbon atoms, an optionally substituted branched hydroxyalkyl group having 4 carbon atoms or a hydroxyl group; and X is 8.

Example 3

An aluminum electrolytic capacitor of the embodiment, wherein an anode of the aluminum electrolytic capacitor has an oxidation voltage of 60 V, comprising a dispersion comprising a conductive polymer, a dispersant, and a polymeric anion, further comprising an additive, wherein the additive is Amide group. The dispersion had a pH of 4 and the dispersion had a viscosity of 200 cps at 20 °C. The conductive polymer had an average particle diameter of 20 nm. The conductive polymer includes a polythiophene derivative, and further includes a polyaniline derivative. The polymeric anion is a polystyrene sulfonate anion, the polystyrene sulfonate anion has a molecular weight of 300,000, and the dispersing agent is water. The polythiophene derivative includes a repeating unit having the composition of the following formula I and formula II, wherein the formula of the formula I is:

The structural formula of the general formula II is:

In the structural formula of the formula I and the formula of the formula II, A is an optionally substituted alkylene group having 2 carbon atoms; and R is an optionally substituted linear cycloalkyl group having 8 carbon atoms. A substituted linear aryl group having 10 carbon atoms, an optionally substituted linear aralkyl group having 10 carbon atoms, and optionally substituted carbon atoms Is a branched hydroxyalkyl group or a hydroxyl group of 3; X is 4.

Example 4

100 g of polystyrenesulfonic acid (molecular weight 25000) was added to 2000 g of deionized water, stirred for 30 minutes, then 50 g of 35% aqueous sodium persulfate solution, 1% aqueous solution of ferric sulfate 14.4 g and 9.1 g of 3,4-dioxane The oxythiophene was uniformly added to the above aqueous solution and stirred for 24 hours. After the completion of the reaction, 200 g of a cationic resin was added to the reaction system, and 200 g of an anion resin was stirred for 2 hours, and the resin was filtered off to obtain a poly(3,4-dialkoxythiophene) polyanion dispersion. With a high pressure homogenizer, it was homogenized 5 times under a pressure of 1000 bar. Then the solid content was tested at 1.34%. The particle size was measured at 10-30 nm using a particle size tester. The viscosity of the dispersion was 150 cps.

100 g of poly(3,4-dialkoxythiophene) polyanion obtained by the above method, 5 g of ethylene glycol, 5 g of polyethylene glycol 600, 0.5 g of 3-glycidoxytrimethoxysilane (Silquest A-187) ), 0.5 g of Dynol 604 (Air product) was mixed in a glass beaker with a magnetic stirrer to form a dispersion B.

The cores of the four specifications were separately contained in the above dispersion B, and then dried at 120 ° C and tested for their properties. The test results are shown in Table 1. Table 1 is a performance test table in which the cores of the four specifications contain the dispersion B.

Table 1 Test results for four cores containing Dispersion B

Example 5

100 g of the poly(3,4-dialkoxythiophene) polyanion dispersion of Example 1, 5 g of dimethyl sulfoxide, 5 g of polyethylene glycol 400, 0.5 g of 3-glycidoxy trimethoxysilane (Silquest A-187), 2 g of sorbitol, 0.5 g of Dynol 604 (Air product) were mixed in a glass beaker with a magnetic stirrer to form a dispersion C.

The cores of the four specifications were separately contained in the dispersion C, and then dried at 120 ° C and tested for their properties. The test results are shown in Table 2. Table 2 is a performance test table in which the cores of the four specifications contain the dispersion C.

Table 2 Test results for four cores containing Dispersion C

Example 6

100 g of the poly(3,4-dialkoxythiophene) polyanion dispersion of Example 1, 5 g of dimethyl sulfoxide, 5 g of polyethylene glycol 200, 0.5 g of 3-glycidoxytrimethoxysilane (Silquest A-187), 2 g xylitol, 0.5 g Dynol 604 (Air product) were mixed in a glass beaker with a magnetic stirrer to form a dispersion D.

The cores of the four specifications were separately contained in Dispersion D, and then dried at 120 ° C and tested for their properties.

The test results are shown in Table 3. Table 3 is a performance test table in which the cores of the four specifications contain the dispersion D.

Table 3 Test results for four cores containing Dispersion D

It can be seen from Table 1-3 that the aluminum electrolytic capacitor of the present application has a capacitance of 10-220 μF, a DF value of 1.4-1.6%, and an equivalent series resistance of 6-18 mΩ, and has an easy discharge, low loss, and low equivalent series resistance. And the advantage of low leakage.

In summary, the aluminum electrolytic capacitor provided by the present application has the advantages of easy discharge, low loss, low equivalent series resistance, and low leakage.

The above content is a further detailed description of the present application in conjunction with the specific embodiments, and the specific implementation of the present application is not limited to the description. For those skilled in the art to which the present invention pertains, a number of simple deductions or substitutions may be made without departing from the inventive concept. All should be considered as falling within the scope of protection of this application.

Claims

An aluminum electrolytic capacitor characterized in that an anode of the aluminum electrolytic capacitor has an oxidation voltage of more than 30 V, and includes a dispersion comprising a conductive polymer and a dispersant, and the conductive polymer has an average particle diameter of 10 -30nm.
The aluminum electrolytic capacitor according to claim 1, wherein said conductive polymer comprises a polythiophene derivative, and said polythiophene derivative comprises a repeating unit having the following formula I and/or formula II; The structural formula of the formula I is:

The structural formula of the general formula II is:

In the structural formula of the formula I and the formula of the formula II, A is an optionally substituted alkylene group having 1 to 5 carbon atoms; R is an optionally substituted direct bond having 5 to 12 carbon atoms or A branched cycloalkyl group, an optionally substituted straight or branched aryl group having 6 to 14 carbon atoms, an optionally substituted linear or branched aralkyl group having 7 to 18 carbon atoms, optionally substituted A linear or branched hydroxyalkyl group having a carbon number of 1 to 4 or a hydroxyl group; and X is an integer of 0-8.
The aluminum electrolytic capacitor according to claim 1, wherein the conductive polymer further comprises at least one of a polypyrrole derivative and a polyaniline derivative.
The aluminum electrolytic capacitor according to claim 1, wherein the dispersion further comprises a polymeric anion.
The aluminum electrolytic capacitor according to claim 4, wherein the polymeric anion is a polymeric carboxylic acid anion or a polymeric sulfonic acid anion.
The aluminum electrolytic capacitor according to claim 4, wherein the polymer anion is a polystyrene sulfonate anion, and the polystyrene sulfonate anion has a molecular weight of from 2,000 to 500,000.
The aluminum electrolytic capacitor according to claim 1, wherein said dispersing agent is organic Solvent and / or water.
The aluminum electrolytic capacitor according to claim 1, wherein the dispersion further comprises at least one of a crosslinking agent, a surfactant, and an additive selected from the group consisting of ethers, lactones, and amide groups. At least one of a lactam group, a sulfone, a sulfoxide, a sugar, a sugar derivative, a sugar alcohol, a furan derivative, a glycol, and a polyol.
The aluminum electrolytic capacitor according to claim 1, wherein the dispersion has a pH of 1.5 to 7, and the dispersion has a viscosity of not more than 500 cps at 20 °C.
A method of producing an aluminum electrolytic capacitor, characterized in that the dispersion is applied to an electrode of an aluminum electrolytic capacitor according to any one of claims 1 to 9, and then the dispersant is partially or completely removed, or The dispersant is cured, and the number of times of removal or curing is one or more times.