PEDOT dispersions with large number of particles

Abstract

The present invention relates to a dispersion comprising i) a dispersant; ii) at least one polythiophene dispersed in the dispersant i); wherein the dispersion comprises particles having a particle size of 1.5 [mu] m or greater, the total number of the particles being in the range of 20,000 / ml to 1,000,000 / ml; and wherein the conductive layer prepared from the dispersion has a surface roughness Rq in the range of 4 nm to 23 nm. The invention also relates to a method for producing a dispersion, to a dispersion obtainable by this method, to a method for producing a layered body, to a layered body obtainable by this method, and to the use of a dispersion for forming a polymer outer layer in a capacitor.

Description

[0001] manual Technical Field

[0002] This invention relates to a dispersion comprising a dispersant and at least one polythiophene dispersed in the dispersant, a method for preparing the dispersion, a dispersion obtainable by the method, a method for preparing a layered body, a layered body obtainable by the method, and the use of the dispersion for forming a polymeric outer layer in a capacitor. Background Technology

[0003] A standard electrolytic capacitor typically consists of porous metal electrodes, an oxide layer disposed on the metal surface, a conductive material (usually solid) introduced into the porous structure, external electrodes (contacts) (such as a silver layer), and other electrical contacts and encapsulation. A commonly used electrolytic capacitor is the tantalum electrolytic capacitor, where the anode electrode is made of the valve metal tantalum, on which a uniform tantalum pentoxide dielectric layer has been created by anodizing (also known as "forming"). A liquid or solid electrolyte forms the cathode of the capacitor. Aluminum capacitors are also frequently used, where the anode electrode is made of the valve metal aluminum, on which a uniform electrically insulating aluminum oxide layer has been created as the dielectric by anodizing. Here, a liquid or solid electrolyte also forms the cathode of the capacitor. Aluminum capacitors are typically embodied as wound capacitors or stacked capacitors.

[0004] Given its high conductivity, - Conjugated polymers are particularly suitable as solid electrolytes in the aforementioned capacitors. - Conjugated polymers, also known as conductive polymers or synthetic metals, are gaining increasing commercial significance due to their advantages over metals in processing, weight control, and selective tuning of properties through chemical modification. Known Examples of conjugated polymers include polypyrrole, polythiophene, polyaniline, polyacetylene, polyphenylene, and poly(p-phenylene-vinylene), among which poly(3,4-ethylene-dioxothiophene) (PEDOT) is a particularly important polythiophene for technical use because it has very high electrical conductivity in its oxidized form.

[0005] In addition to low equivalent series resistance (ESR), modern electrolytic capacitors also require low leakage current and good stability relative to external stress. High mechanical stresses, in particular, can significantly increase the leakage current at the capacitor anode during the manufacturing process of the encapsulated capacitor anode.

[0006] The stability against such stresses and the resulting low leakage current are primarily achieved through an outer layer of approximately 5 μm to 50 μm thick made of conductive polymer on the capacitor anode. This layer acts as a mechanical buffer between the capacitor anode and cathode-side electrodes. This prevents the silver layer (contact) from directly contacting or damaging the dielectric, for example, under mechanical stress, thereby increasing the capacitor's leakage current.

[0007] In the prior art, PEDOT / PSS dispersions are used not only to form a solid electrolyte layer but also to form a polymer outer layer to be applied on top of the solid electrolyte layer. For example, DE-A-10 2005 033 839 discloses the use of a dispersion comprising conductive polymer particles and a binder for forming a polymer outer layer, wherein the proportion of conductive polymer particles with a diameter less than 700 nm in the dispersion forms a solid content of at least 5% by weight of the solid content of the dispersion, and wherein the dispersion further comprises solid particles with a diameter in the range of 0.7 μm to 20 μm.

[0008] However, it has been observed that for some applications, the leakage current of solid electrolyte capacitors is often too high, and the polymer outer layer of these solid electrolyte capacitors has been prepared using PEDOT / PSS-based dispersions (such as those disclosed in DE-A-10 2005 033839).

[0009] This invention aims to overcome the limitations of existing technologies related to capacitors, particularly solid electrolytic capacitors, and more preferably capacitors known from the prior art that include a polymer outer layer on top of a solid electrolyte layer (wherein the polymer outer layer is based on...). - The disadvantages associated with conjugated polymers such as PEDOT, and even more preferably with capacitors that include a polymer outer layer based on PEDOT / PSS, as known from the prior art.

[0010] Specifically, the present invention aims to provide a dispersion comprising at least one polythiophene, preferably a dispersion comprising a polythiophene and a polyanionic complex, more preferably a dispersion comprising a PEDOT / PSS complex, which are particularly useful for preparing polymeric outer layers in capacitors characterized by low leakage current.

[0011] Another object of the present invention is to provide a method by which such advantageous dispersions can be prepared. The method for preparing advantageous dispersions should be characterized in that it allows these dispersions to be manufactured in the simplest possible manner, and in particular with the fewest possible method steps.

[0012] Furthermore, the object of the present invention is to provide a method for preparing a layered structure, preferably for preparing an electrolyte capacitor, wherein the electrolyte capacitor is characterized by a reduced leakage current compared to electrolyte capacitors known from the prior art. Summary of the Invention

[0013] The independent claims contribute to at least partially solving at least one of the above-described objectives, preferably more than one. The dependent claims provide preferred embodiments that help to at least partially solve at least one of the stated objectives.

[0014] A first embodiment of the dispersion contributes to solving at least one of the objectives according to the invention, the dispersion comprising:

[0015] i) Dispersants (also known as "dispersion reagents");

[0016] ii) At least one polythiophene dispersed in the dispersant i);

[0017] The dispersion contains particles with a size of 1.5 μm or larger, and the total number of these particles is 20,000 (i.e., 2 × 10⁻⁶). 4 The concentration is in the range of 50,000 / ml to 900,000 / ml, more preferably in the range of 75,000 / ml to 900,000 / ml, and even more preferably in the range of 100,000 / ml to 900,000 / ml; and

[0018] The surface roughness Rq of the conductive layer prepared from the dispersion is in the range of 4 nm to 23 nm, preferably in the range of 4 nm to 20 nm, more preferably in the range of 4 nm to 15 nm, and even more preferably in the range of 4 nm to 10 nm.

[0019] In the context of this invention, the term "dispersion" generally refers to any liquid composition (dispersant i) in which polythiophene (e.g., polythiophene as part of a complex comprising polythiophene and a polyanion) is distributed in a certain way in a homogeneous phase formed by a liquid dispersant i, thus forming a dispersion (the liquid phase). It should be noted that the transition between "dispersion" and "solution" can be fluid. For this reason, no distinction is made below between the terms "dispersed" and "dissolved." Similarly, no distinction is made between "dispersion" and "solution" or between "dispersant" and "solvent." Rather, these terms are used synonymously below.

[0020] According to a preferred embodiment of the dispersion according to the invention, the dispersion comprises more than 1,500 particles per milliliter, preferably more than 2,000 particles per milliliter, more preferably more than 3,000 particles per milliliter, and even more preferably more than 5,000 particles per milliliter, wherein the particle size is 10 μm or larger. This preferred embodiment is a second embodiment of the dispersion according to the invention, which preferably depends on the first embodiment.

[0021] According to another preferred embodiment of the dispersion according to the invention, the polythiophene (ii) exists in the form of particles comprising a complex of the polythiophene and the polyanion, and wherein the number and size of particles defined in the first and second embodiments of the dispersion according to the invention refer to the number and size of particles comprising the complex of the polythiophene and the polyanion. This preferred embodiment is a third embodiment of the dispersion according to the invention, which preferably depends on either the first or second embodiment.

[0022] According to a preferred embodiment of the dispersion according to the invention, the dispersant i) comprises water. Preferably, the dispersant i) comprises at least 50% by weight, more preferably at least 65% by weight, even more preferably at least 70% by weight, and most preferably at least 80% by weight of water based on the total weight of the dispersion in each case. This preferred embodiment is a fourth embodiment of the dispersion according to the invention, which preferably depends on any one of the first to third embodiments.

[0023] According to another preferred embodiment of the dispersion according to the invention, the at least one polythiophene (ii) is an externally doped polythiophene such as cationic polythiophene existing in the form of a polythiophene / polyanionic complex, more preferably in the form of a PEDOT / PSS complex, a self-doped polythiophene such as poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxane-2-yl)methoxy]propane-1-sulfonic acid), poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxane-2-yl)methoxy]butane-1-sulfonic acid) (PEDOT-S) or poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxane-2-yl)methoxy]butane-2-sulfonic acid), or a mixture thereof. This preferred embodiment is a fifth embodiment of the dispersion according to the invention, which preferably depends on any one of the first to fourth embodiments.

[0024] According to another preferred embodiment of the dispersion according to the invention, the at least one polythiophene (ii) exists in the form of particles comprising a complex of the at least one polythiophene (ii) and a polyanion. This preferred embodiment is a sixth embodiment of the dispersion according to the invention, which preferably depends on any one of the first to fifth embodiments.

[0025] According to another preferred embodiment of the dispersion according to the invention, the at least one polythiophene (ii) exists in the form of particles comprising a complex of the at least one polythiophene (ii) and a polyanion, wherein the polythiophene is poly(3,4-ethylenedioxythiophene) and the polyanion is an anion of polystyrene sulfonate. Therefore, the polythiophene-polyanion complex is preferably a PEDOT / PSS complex. This preferred embodiment is a seventh embodiment of the dispersion according to the invention, which preferably depends on any one of the first to sixth embodiments.

[0026] According to another preferred embodiment of the dispersion according to the invention, the at least one polythiophene (ii) is present in the form of particles comprising a complex of the at least one polythiophene (ii) and a polyanion, preferably in the form of particles comprising PEDOT / PSS, wherein the weight ratio of the polyanion to the polythiophene in the dispersion is in the range of 0.5:1 to 30:1, preferably in the range of 0.8:1 to 15:1, more preferably in the range of 1:1 to 10:1, even more preferably in the range of 1.2:1 to 8:1, and most preferably in the range of 1.4:1 to 4:1. In this context, assuming complete conversion occurs during polymerization, the weight of the polythiophene corresponds to the weighing of the thiophene monomer used to prepare the polythiophene. This preferred embodiment is an eighth embodiment of the dispersion according to the invention, which preferably depends on any one of the first to seventh embodiments.

[0027] According to another preferred embodiment of the dispersion according to the invention, the at least one polythiophene (ii) exists in the form of particles comprising a complex of the at least one polythiophene (ii) and a polyanion, preferably in the form of particles comprising PEDOT / PSS, wherein the weight-average diameter (d) of these particles is determined by ultracentrifugation measurements. 50The wavelength range is in the range of 10 nm to 500 nm, more preferably in the range of 20 nm to 400 nm, even more preferably in the range of 30 nm to 300 nm, and most preferably in the range of 40 nm to 300 nm. This preferred embodiment is a ninth embodiment of the dispersion according to the invention, which preferably depends on any one of the first to eighth embodiments.

[0028] According to another preferred embodiment of the dispersion according to the invention, the at least one polythiophene (ii) exists in the form of particles comprising a complex of the at least one polythiophene (ii) and a polyanion, preferably in the form of particles comprising PEDOT / PSS, wherein the diameter distribution of these particles in the dispersion, as determined by ultracentrifugation, is d 90 The value is less than 1,000 nm, preferably less than 800 nm, more preferably less than 600 nm, and most preferably less than 500 nm. This preferred embodiment is a tenth embodiment of the dispersion according to the invention, which preferably depends on any one of the first to ninth embodiments.

[0029] According to another preferred embodiment of the dispersion according to the invention, the at least one polythiophene (ii) exists in the form of particles comprising a complex of the at least one polythiophene (ii) and a polyanion, preferably in the form of particles comprising PEDOT / PSS, wherein the dispersion is such that the diameter distribution of these particles is determined by ultracentrifugation measurement. 10 The value is greater than 2 nm, preferably greater than 5 nm, more preferably greater than 10 nm, and most preferably greater than 20 nm. This preferred embodiment is an eleventh embodiment of the dispersion according to the invention, which preferably depends on any one of the first to tenth embodiments.

[0030] According to another preferred embodiment of the dispersion according to the invention, the solids content of the dispersion is at least 1% by weight, preferably at least 1.4% by weight, more preferably at least 1.6% by weight, even more preferably at least 1.8% by weight, and most preferably at least 2.0% by weight, based on the total weight of the dispersion in each case. This preferred embodiment is a twelfth embodiment of the dispersion according to the invention, which preferably depends on any one of the first to eleventh embodiments.

[0031] According to another preferred embodiment of the dispersion according to the invention, the pH value of the dispersion (determined at 25°C) is in the range of 1 to 8.0, preferably in the range of 1.5 to 7, and more preferably in the range of 2.5 to 6. This preferred embodiment is a thirteenth embodiment of the dispersion according to the invention, which preferably depends on any one of the first to twelfth embodiments.

[0032] According to another preferred embodiment of the dispersion according to the invention, the conductivity of the conductive layer prepared from the dispersion is at least 10 S / cm, preferably at least 50 S / cm, more preferably at least 100 S / cm, and most preferably at least 200 S / cm, as determined by the test method disclosed herein (i.e., by a test method wherein the conductivity of the conductive layer is determined for a dispersion obtained after 1 g of DMSO has been added to 19 g of the dispersion according to the invention). This preferred embodiment is a fourteenth embodiment of the dispersion according to the invention, which preferably depends on any one of the first to thirteenth embodiments.

[0033] According to another preferred embodiment of the dispersion according to the invention, the at least one polythiophene (ii) is present in the form of particles comprising a complex of the at least one polythiophene (ii) and a polyanion, preferably in the form of particles comprising PEDOT / PSS, wherein the total amount of the polythiophene and the polyanion contained in the dispersion (i.e., the amount of polythiophene plus the amount of polyanion) is at least 1% by weight, preferably at least 1.4% by weight, more preferably at least 1.6% by weight, even more preferably at least 1.7% by weight, and most preferably at least 1.8% by weight, based on the total weight of the dispersion in each case. This preferred embodiment is a fifteenth embodiment of the dispersion according to the invention, which preferably depends on any one of the first to fourteenth embodiments.

[0034] According to another preferred embodiment of the dispersion according to the invention, the dispersion further comprises:

[0035] iii) at least one additive, wherein the at least one additive is an additive selected from the group consisting of: binders, pH adjusters, crosslinking agents, adhesion promoters, conductivity improvers, surfactants, stabilizers, and combinations of at least two of these additives.

[0036] This preferred embodiment is the sixteenth embodiment of the dispersion according to the invention, which preferably depends on any one of the first to fifteenth embodiments.

[0037] According to another preferred embodiment of the dispersion according to the invention, the dispersion further comprises the following as additives:

[0038] iii) At least one organic binder, preferably at least one organic binder selected from the group consisting of: polyolefins, polyvinyl acetate, polycarbonate, polyvinyl butyral, polyacrylate, polyacrylamide, polymethacrylate, polymethacrylamide, polystyrene, polyacrylonitrile, polyvinyl chloride, polyvinylpyrrolidone, polybutadiene, polyisoprene, polyether, polyester, polyurethane, polyamide, polyimide, polysulfone, polysiloxane, epoxy resin, styrene-acrylate, vinyl acetate / acrylate and ethylene / vinyl acetate copolymer, polyvinyl alcohol or cellulose derivatives and mixtures thereof.

[0039] Preferably, the dispersion contains an amount of organic binder in each case ranging from 0.1 wt% to 20 wt%, preferably from 0.5 wt% to 15 wt%, more preferably from 1 wt% to 10 wt%, and even more preferably from 1 wt% to 5 wt%, based on the total weight of the dispersion. This preferred embodiment is a seventeenth embodiment of the dispersion according to the invention, which preferably depends on the sixteenth embodiment.

[0040] According to another preferred embodiment of the dispersion according to the invention, the viscosity of the dispersion (at 20°C and in 100s) is... -1 The shear rate (measured by a rheometer) is in the range of 1 mPa×s to 1000 mPa×s, preferably in the range of 5 mPa×s to 750 mPa×s, more preferably in the range of 10 mPa×s to 500 mPa×s, and most preferably in the range of 20 mPa×s to 300 mPa×s. This preferred embodiment is the eighteenth embodiment of the dispersion according to the invention, which preferably depends on any one of the first to seventeenth embodiments.

[0041] A first embodiment of method 1 for preparing a dispersion also contributes to solving at least one of the objectives according to the invention, the method comprising the following steps:

[0042] I) Provides a dispersion comprising:

[0043] i) Dispersant;

[0044] ii) At least one polythiophene dispersed in the dispersant i);

[0045] By polymerizing thiophene monomers in the presence of dispersant i);

[0046] II) Adjust the size of particles with a particle size of 1.5 μm or larger in the dispersion provided in step I) to be in the range of 20,000 / ml to 1,000,000 / ml, preferably in the range of 50,000 / ml to 900,000 / ml, more preferably in the range of 75,000 / ml to 900,000 / ml, and even more preferably in the range of 100,000 / ml to 900,000 / ml.

[0047] According to a preferred embodiment of method 1 according to the invention, the dispersant i) comprises water. Preferably, the dispersant i) comprises at least 50% by weight, more preferably at least 65% by weight, even more preferably at least 70% by weight, and most preferably at least 80% by weight of water based on the total weight of the dispersion in each case. This preferred embodiment is a second embodiment of method 1 according to the invention, which preferably depends on the first embodiment.

[0048] According to another preferred embodiment of method 1 of the present invention, the thiophene monomer is polymerized in the presence of the dispersant i) and the polyanion to obtain a dispersion comprising a complex of polythiophene and the polyanion. This preferred embodiment is a third embodiment of method 1 of the present invention, which preferably depends on the first embodiment or the second embodiment.

[0049] According to another preferred embodiment of method 1 of the present invention, the thiophene monomer is polymerized in the presence of the dispersant i) and the polyanion to obtain a dispersion comprising a complex of polythiophene and a polyanion, wherein the thiophene monomer is 3,4-ethylenedioxythiophene and the polyanion is an anion of polystyrene sulfonate. Therefore, the polythiophene-polyanion complex is preferably a PEDOT / PSS complex. This preferred embodiment is a fourth embodiment of method 1 of the present invention, which preferably depends on any one of the first to third embodiments.

[0050] According to another preferred embodiment of method 1 of the present invention, the adjustment of the number of particles with a particle size of 1.5 μm or larger in the dispersion provided in method step I) is achieved by means of a method comprising the following steps:

[0051] IIa) subjecting the dispersion obtained in step I) to a first filtration step, wherein the dispersion is filtered through a filter with a cutoff size in the range of 100 μm to 150 μm, preferably in the range of 120 μm to 130 μm.

[0052] IIb) subjecting the dispersion obtained in step IIa) to a further filtration step, wherein the dispersion is filtered through a filter with a cutoff size in the range of 1 μm to 50 μm, preferably in the range of 5 μm to 15 μm, wherein the filtration is preferably performed at a pressure not exceeding 1 bar, preferably not exceeding 0.8 bar, more preferably not exceeding 0.6 bar, even more preferably not exceeding 0.4 bar, and most preferably not exceeding 0.2 bar.

[0053] This preferred embodiment is a fifth embodiment of method 1 according to the present invention, which preferably depends on any one of the first to fourth embodiments.

[0054] According to another preferred embodiment of method 1 of the present invention, the adjustment of the number of particles with a particle size of 1.5 μm or larger in the dispersion provided in method step I) is achieved by means of a method comprising the following steps:

[0055] IIa) Separate a portion of the dispersion obtained in step i) from the dispersion, preferably 80% to 94% by weight, more preferably 88% to 92% by weight, and subject the separated portion to at least eight, preferably at least ten, high-pressure homogenization steps (these high-pressure homogenization steps are performed at a pressure of up to 2000 bar, preferably at a pressure of up to 1500 bar), followed by a filtration step, wherein the dispersion is filtered through a filter with a cutoff size in the range of 3 μm to 8 μm, preferably in the range of 4 μm to 5 μm;

[0056] IIb) subject the remaining portion of the dispersion provided in step i) to a removal step, wherein the ion exchange resin is removed through a 400 μm filter.

[0057] IIc) The filtered portion of the resulting dispersion is then recombined.

[0058] This preferred embodiment is the sixth embodiment of method 1 according to the present invention, which preferably depends on any one of the first to fourth embodiments.

[0059] The dispersion also contributes to achieving at least one of the objectives according to the invention, and the dispersion can be obtained by method 1 according to the invention, preferably by method 1 according to any one of the first to sixth embodiments. Preferably, the dispersion has the same properties as the dispersion according to the invention, and preferably the same properties as the dispersion according to the invention as defined in any one of the first to eighteenth embodiments.

[0060] A first embodiment of method 2 for preparing a lamellar body also contributes to solving at least one of the objectives according to the invention, the method comprising the following steps:

[0061] A) Provide the substrate;

[0062] B) Apply the dispersion according to the invention, preferably the dispersion according to the invention as defined in any one of the first to eighteenth embodiments, or the dispersion that can be obtained by method 1 according to the invention, preferably by method 1 as defined in any one of the first to sixth embodiments, to at least a portion of the surface of the substrate;

[0063] C) At least partially remove the dispersant i) to obtain a layer comprising a conductive layer coated on at least a portion of the surface of the substrate.

[0064] According to a preferred embodiment of method 2 of the present invention, the layered body is part of a solid electrolyte capacitor, wherein the substrate is a porous electrode body made of an electrode material, wherein a dielectric layer at least partially covers the surface of the electrode material, wherein a solid electrolyte layer at least partially covers the surface of the dielectric layer, and wherein the conductive layer is a polymer outer layer that at least partially covers the surface of the solid electrolyte layer. This preferred embodiment is a second embodiment of method 2 of the present invention, which preferably depends on the first embodiment.

[0065] According to a preferred embodiment of method 2 of the present invention, the method includes the following steps:

[0066] A) Provides a porous electrode body made of an electrode material, wherein a dielectric layer at least partially covers the surface of the electrode material, and wherein a solid electrolyte layer at least partially covers the surface of the dielectric layer;

[0067] B) Apply the dispersion according to the invention, preferably the dispersion according to the invention as defined in any one of the first to eighteenth embodiments, or the dispersion that can be obtained by method 1 according to the invention, preferably by method 1 as defined in any one of the first to sixth embodiments, to at least a portion of the surface of the solid electrolyte layer;

[0068] C) At least partially remove the dispersant i) to form a polymer outer layer that at least partially covers the surface of the solid electrolyte layer.

[0069] This preferred embodiment is a third embodiment of method 2 according to the present invention, which preferably depends on the first embodiment or the second embodiment.

[0070] According to another preferred embodiment of method 2 of the present invention, the layered body is an aluminum capacitor or a tantalum capacitor. This preferred embodiment is a fourth embodiment of method 2 of the present invention, which preferably depends on any one of the first to third embodiments.

[0071] The layered structure also contributes to achieving at least one of the objectives according to the invention, which can be obtained by method 2 according to the invention, preferably by method 2 according to any one of its first to fourth embodiments.

[0072] The use of the dispersion according to the invention, preferably the dispersion according to the invention as defined in any one of the first to eighteenth embodiments, or the dispersion that can be obtained by method 1 according to the invention, preferably by method 1 as defined in any one of the first to sixth embodiments, for forming a polymer outer layer in a capacitor also contributes to solving at least one of the objectives according to the invention.

[0073] According to a preferred embodiment of the application of the invention, the capacitor is an aluminum capacitor or a tantalum capacitor. This preferred embodiment is a second embodiment of the application of the invention, which preferably depends on the first embodiment. Detailed Implementation

[0074] Polythiophene

[0075] The dispersion according to the invention comprises a dispersant and at least one polythiophene dispersed in the dispersant.

[0076] Preferred polythiophenes are those having repeating units of general formula (I), general formula (II), or general formula (III), or combinations thereof:

[0077]

[0078] (I)(II)

[0079]

[0080] (III)

[0081] in

[0082] A is an optionally substituted C1-C5-alkylene group.

[0083] R is independently H, a linear or branched, optionally substituted C1-C 18 -alkyl group, optionally substituted C5-C 12 - Cycloalkyl group, optionally substituted C6-C 14 -Aryl group, optionally substituted C7-C 18 -Aryl group, optionally substituted C1-C4-hydroxyalkyl group or hydroxy group,

[0084] x is an integer from 0 to 8, and

[0085] When multiple R groups are bonded to A, they can be the same or different.

[0086] General formulas (I) and (II) should be understood as allowing the x-substituent R to bond with the alkylene group A.

[0087] Particularly preferred polythiophenes have repeating units of general formula (I) or (II), or repeating units of general formulas (I) and (II), wherein A is an optionally substituted C2-C3-alkylene group and x is 0 or 1. Very particularly preferred polythiophenes are poly(3,4-ethylenedioxythiophene) (PEDOT), which is optionally substituted with poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxane-2-yl)methoxy]propane-1-sulfonic acid), poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxane-2-yl)methoxy]butane-1-sulfonic acid) (PEDOT-S) or poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxane-2-yl)methoxy]butane-2-sulfonic acid).

[0088] In the context of this invention, the prefix "poly" should be understood to refer to the presence of more than one identical or different repeating unit in the polymer or polythiophene. The polythiophene comprises a total of n repeating units of general formula (I), or general formula (II), or general formula (III), or general formulas (I) and (II), or general formulas (I) and (III), or general formulas (II) and (III), or general formulas (I), (II), and (III), where n is an integer from 2 to 2000, preferably from 2 to 100. The repeating units of general formula (I), or general formula (II), or general formula (III), or repeating units of general formulas (I) and (II), or repeating units of general formulas (I) and (III), or repeating units of general formulas (II) and (III), or repeating units of general formulas (I), (II), and (III) may each be identical or different in the polythiophene. Preferred polythiophenes have the same repeating unit of general formula (I), general formula (II), or general formula (III) in each case, or the same repeating unit of general formula (I) and (II), or general formula (I) and (III), or general formula (II) and (III) in each case, or the same repeating unit of general formula (I), (II), and (III) in each case. Particularly preferred polythiophenes have the same repeating unit of general formula (I) or general formula (II) in each case, or the same repeating unit of general formula (I) and (II) in each case. At the end groups, the polythiophenes preferably each carry H.

[0089] In the context of this invention, the C1-C5-alkylene group A is preferably methylene, ethylene, n-propylene, n-butylene, or n-pentylene. 18 -alkyl group R is preferably a straight-chain or branched C1-C group. 18 -alkyl groups, such as methyl, ethyl, n-propyl or isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1-ethylpropyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-hexadecyl or n-octadecyl, C5-C 12 -The cycloalkyl group R is, for example, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, or cyclodecyl, C6-C 14 -The aryl group R is, for example, phenyl or naphthyl, and C7-C 18The aryl group R is, for example, benzyl, o-tolyl, m-tolyl, p-tolyl, 2,3-xylyl, 2,4-xylyl, 2,5-xylyl, 2,6-xylyl, 3,4-xylyl, 3,5-xylyl, or mesitylene. The foregoing examples are for illustrative purposes only and should not be considered exclusive.

[0090] In the context of this invention, any additional substituents of the A group and / or R group include a number of organic groups, such as alkyl, cycloalkyl, aryl, aralkyl, alkoxy, halogen, ether, thioether, disulfide, sulfoxide, sulfone, sulfonate, amino, aldehyde, ketone, carboxylic acid ester, carboxylic acid, carbonate, carboxylic acid ester, cyano, alkylsilane and alkoxysilyl groups, as well as formamide groups.

[0091] Polythiophenes can be uncharged or cationic. In preferred embodiments, they are cationic, and "cationic" refers only to the charge remaining on the main polythiophene chain. Depending on the substituents on the R groups, polythiophenes can carry both positive and negative charges within the structural units, in which case the positive charge is on the polythiophene backbone and the negative charge (if present) is on the R groups substituted with sulfonate or carboxylate groups. The positive charge on the polythiophene backbone can be partially or completely saturated by anionic groups that may be present on the R groups. In general, polythiophenes in these cases can be cationic, uncharged, or even anionic. However, in the context of this invention, all are considered cationic polythiophenes because the positive charge on the polythiophene backbone is crucial. The positive charge is not shown in the formula because its precise quantity and location cannot be explicitly represented. However, the number of positive charges is at least 1 and at most n, where n is the total number of all repeating units (identical or different) within the polythiophene.

[0092] The positive charge of polythiophene can be balanced by R groups that are substituted with sulfonates or carboxylates and are therefore negatively charged (so-called "self-doped polythiophene") or by counterions (so-called "externally doped polythiophene").

[0093] According to a first preferred embodiment of the polythiophene in the dispersion according to the invention, the polythiophene is a self-doped polythiophene, which preferably comprises at least 50%, more preferably at least 75%, more preferably at least 95%, and most preferably 100% of repeating units of formula (IV).

[0094]

[0095] (IV)

[0096] in

[0097] X and Y are the same or different, and represent O, S, NR. 1 ,

[0098] Where R 1 Indicates aryl, C1-C 18 -alkyl or hydrogen;

[0099] Z is an organic group carrying an anionic functional group, preferably an organic group carrying an anionic functional group. The group, particularly preferred being Z, represents –(CH2). m –CR 2 R 3 –(CH2) n –,

[0100] R 2 It represents hydrogen, –(CH2). s –O–(CR 4 2) p -SO3 - M + or ,

[0101] R 3 It represents –(CH2) s –O–(CR 4 2) p -SO3 - M + or ,

[0102] M + Indicates a cation.

[0103] m and n can be the same or different, and represent integers from 0 to 3.

[0104] R 4 Indicates hydrogen or C1-C 10 Alkyl groups, preferably methyl groups,

[0105] s represents an integer from 0 to 10, and

[0106] p represents an integer from 1 to 18.

[0107] In this context, the percentage figures above are intended to represent the numerical content of units of structural formula (IV) out of the total number of monomer units in a self-doped conductive polymer.

[0108] Suitable cation M + For example, H + Li + Na + K + 、Rb + Cs +and NH4 + A particularly suitable cation is Na. + and K + .

[0109] A particularly preferred monomer of structural formula (IV) is a monomer in which...

[0110] X and Y represent O,

[0111] Z represents –(CH2) m –CR 2 R 3 –(CH2) n –,

[0112] R 2 Indicates hydrogen or , or- ,

[0113] R 3 express , Or –(CH2) s –O– ,

[0114] M + Indicates a cation.

[0115] m and n can be the same or different, and represent integers from 0 to 3.

[0116] R 4 Indicates hydrogen, methyl group, or ethyl group;

[0117] s represents an integer from 0 to 10, and

[0118] p represents an integer from 1 to 18.

[0119] A particularly preferred monomer of structural formula (IV) is a monomer in which...

[0120] X and Y represent O,

[0121] Z represents –(CH2)–CR 2 R 3 –(CH2) n –,

[0122] R 2 It represents hydrogen.

[0123] R 3 express , or or ,

[0124] M + Na represents + or K + ,

[0125] n represents 0 or 1,

[0126] s represents 0 or 1, and

[0127] p represents 2, 3, 4 or 5.

[0128] Suitable examples of self-doped polymers are disclosed in WO-A-2014 / 048562 and US-A-2015 / 0337061. Specific examples of very particularly preferred self-doped conductive polymers include poly(4-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxane-2-yl)methoxy]propane-1-sulfonic acid), poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxane-2-yl)methoxy]butane-1-sulfonic acid) (PEDOT-S), poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxane-2-yl)methoxy]butane-2-sulfonic acid), or mixtures thereof.

[0129] According to a second preferred embodiment of the polythiophene in the dispersion according to the invention, the polythiophene is an externally doped polythiophene, which preferably contains a polymer counterion to balance the positive charge; the polymer counterion is also referred to hereinafter as a "polyanion". Therefore, according to a preferred embodiment of the dispersion according to the invention, the polythiophene is a cationic polythiophene containing a polyanion that acts as a counterion to the polythiophene.

[0130] Polyanions are preferred over monomeric anions because they facilitate film formation and, due to their size, result in more thermally stable conductive films. The polyanions herein can be, for example, anions of polymeric carboxylic acids (such as polyacrylic acid, polymethacrylic acid, or polymaleic acid) or polymeric sulfonic acids (such as polystyrene sulfonic acid and polyethylene sulfonic acid). These polycarboxylic acids and sulfonic acids can also be copolymers of ethylene carboxylic acid and ethylene sulfonic acid with other polymerizable monomers (such as acrylates and styrene).

[0131] Preferred polyanions are anions of polymeric carboxylic acids or sulfonic acids. Particularly preferred polyanions are anions of polystyrene sulfonic acid (PSS) or its derivatives.

[0132] The molecular weight of the polyanionic polyacid is preferably from 1,000 to 2,000,000, more preferably from 2,000 to 500,000. The polyacid or its alkali metal salt is commercially available, for example, polystyrene sulfonic acid and polyacrylic acid, or can be prepared by known processes (see, for example, Houben Weyl, Methods of Organischen Chemie, Vol. E 20, Makromolekulare Stoffe, Part 2, (1987), p. 1141 and subsequent pages).

[0133] A particularly preferred example of an externally doped polythiophene is a complex of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonate anion (PEDOT / PSS).

[0134] Other additives

[0135] According to a preferred embodiment of the dispersion according to the invention, the dispersion further comprises at least one additive, wherein the at least one additive is an additive selected from the group consisting of: binders, pH adjusters, crosslinking agents, adhesion promoters, conductivity improvers, surfactants, stabilizers, and combinations of at least two of these additives.

[0136] Suitable binders include organic binders that are particularly soluble in organic solvents, such as polyolefins, polyvinyl acetate, polycarbonate, polyvinyl butyral, polyacrylate, polyacrylamide, polymethacrylate, polymethacrylamide, polystyrene, polyacrylonitrile, polyvinyl chloride, polyvinylpyrrolidone, polybutadiene, polyisoprene, polyether, polyester, polyurethane, polyamide, polyimide, polysulfone, polysiloxane, epoxy resin, styrene-acrylate, vinyl acetate / acrylate and ethylene / vinyl acetate copolymers, polyvinyl alcohol, or cellulose derivatives may also be added to the composition. Copolymers of the above polymers are also suitable as binders.

[0137] Suitable pH adjusters include, for example, the bases or acids described on page 4, lines 13-32 of WO 2010 / 003874 A2. Preferred additives are those that do not impair film formation of the dispersion and do not volatilize at relatively high temperatures (e.g., at welding temperatures), but remain within the solid electrolyte under these conditions. Particularly suitable are compounds such as the bases 2-dimethylaminoethanol, 2,2'-iminodiethanol, or 2,2',2'-nitrotriethanol and the acid polystyrene sulfonic acid.

[0138] Suitable crosslinking agents include melamine compounds, capped isocyanates, functional silanes (e.g., tetraethoxysilanes), alkoxysilane hydrolysis products (e.g., tetraethoxysilane-based hydrolysis products), or epoxysilanes (such as 3-glycidoxypropyltrialkoxysilane).

[0139] Suitable adhesion promoters include organofunctional silanes or their hydrolysis products, such as 3-glycidoxypropyltrialkoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, vinyltrimethoxysilane, or octyltriethoxysilane.

[0140] Suitable conductivity improvers include compounds such as tetrahydrofuran, compounds containing lactone groups such as butyrolactone and valproic acid, compounds containing amide or lactam groups such as caprolactam, N-methylcaprolactam, N,N-dimethylacetamide, N-methylacetamide, N,N-dimethylformamide (DMF), N-methylformamide, N-methylformanilide, N-methylpyrrolidone (NMP), N-octylpyrrolidone, pyrrolidone, sulfones and sulfoxides such as sulfolane (tetramethylene sulfone) and dimethyl sulfoxide (DMSO), sugars or sugar derivatives such as sucrose, glucose, fructose, and lactose, sugar-based surfactants such as Tween or Span 60, sugar alcohols such as sorbitol and mannitol, furan derivatives such as 2-furancarboxylic acid and 3-furancarboxylic acid, and / or diols or polyols such as ethylene glycol, glycerol, diethylene glycol, triethylene glycol, or polyglycerol. Ethylene glycol, diethylene glycol, triethylene glycol, polyglycerol, dimethyl sulfoxide, or sorbitol are particularly preferred as conductivity-improving additives.

[0141] Suitable surfactants include: anionic surfactants, such as alkylbenzene sulfonic acids and salts, paraffin sulfonates, alcohol sulfonates, ether sulfonates, sulfosuccinates, phosphate esters, alkyl ether carboxylic acids, or carboxylates; cationic surfactants, such as quaternary alkylammonium salts; and nonionic surfactants, particularly nonionic amphiphilic surfactants, such as linear or branched alcohol ethoxylates, carbonyl synthetic alcohol ethoxylates, alkylphenol ethoxylates, or alkyl polyglucosides. Representative examples of suitable surfactants include fluorinated surfactants, such as ZONYL. ® Surfactants, including ZONYL ® FSN, ZONYL ® FSO, ZONYL ® FSA, ZONYL ® FSH (DuPont Chemicals, Wilmington, Del.) and NOVEC ®(3M, St. Paul, Minn.) Other exemplary surfactants include nonionic surfactants based on alkylphenol ethoxylates. Preferred surfactants include, for example, octylphenol ethoxylates such as TRITON. ® and secondary alcohol ethoxylates such as TERGITOL ® 15-S series (Dow Chemical Company, Midland Mich.). Other exemplary nonionic surfactants include acetylene-based surfactants, n-dodecyl β-D-maltodextrin, and alcohol ethoxylates, such as TERGITOL. ® TMN.

[0142] Suitable stabilizers are those compounds mentioned in WO 2012 / 041507 A1, with aromatic compounds containing at least two OH groups and an additional functional group having a heteroatom other than carbon being particularly preferred. Examples of suitable stabilizers are 3,4,5-trihydroxybenzoic acid and its derivatives, such as 3,4,5-trihydroxybenzoic acid esters (gallic acid esters), and will also be mentioned in particular alkyl esters, alkenyl esters, cycloalkyl esters, cycloalkenyl esters, and aryl esters, which in each case preferably have 1 to 15 carbon atoms in the aryl or alkyl group of the ester. Gallic acid and glycoesterified gallic acid are particularly preferred, which are commonly referred to as tannins or gallotannins (see Römpp Chemie, 10th edition (1999), p. 4391). Also suitable as stabilizers are “hydroxy-group-containing aromatic compounds” mentioned in paragraph

[0049] of EP 1 798 259 A1, “antioxidants” mentioned in paragraph

[0025] of EP 1 043 720 A1, and “aromatic compounds exclusive of sulfo groups and containing at least two hydroxy groups” mentioned on pages 10 and 11 of WO 2008 / 055834 A1.

[0143] Methods for producing capacitors

[0144] According to a preferred embodiment of the method for preparing a layered structure according to the present invention, the layered structure is part of an electrolyte capacitor. In this case, the method includes the following steps:

[0145] A) Provides a porous electrode body made of an electrode material, wherein a dielectric layer at least partially covers the surface of the electrode material, and wherein a solid electrolyte layer at least partially covers the surface of the dielectric layer;

[0146] B) Apply the dispersion according to the invention, preferably the dispersion according to the invention as defined in any one of the first to eighteenth embodiments, or the dispersion that can be obtained by method 1 according to the invention, preferably by method 1 as defined in any one of the first to seventh embodiments, to at least a portion of the surface of the solid electrolyte layer;

[0147] C) At least partially remove the dispersant i) to form a polymer outer layer that at least partially covers the surface of the solid electrolyte layer.

[0148] Method Step A):

[0149] In method step A), a porous electrode body made of an electrode material is provided, wherein a dielectric layer at least partially covers the surface of the electrode material, and wherein a solid electrolyte layer at least partially covers the surface of the dielectric layer.

[0150] In principle, the porous electrode body can be manufactured by pressing and sintering valve metal powder with a high surface area to form the porous electrode body. In this context, electrical contact wires, preferably made of valve metal (such as tantalum), are conventionally pressed into the porous electrode body. The porous electrode body is then coated, for example, by electrochemical oxidation with a dielectric, i.e., an oxide layer. Alternatively, a metal film can be etched and coated with an electrochemical oxidation dielectric to obtain an anode film with porous regions. In the case of a wound capacitor, the anode film with porous regions (which forms the electrode body) and the cathode film are separated by a separator and wound.

[0151] Within the scope of this invention, metals whose oxide coatings prevent the uniform flow of current in both directions are considered valve metals. When a voltage is applied to the anode, the oxide layer of a valve metal impedes current flow, while when a voltage is applied to the cathode, a considerable current can occur, which can destroy the oxide layer. Valve metals include Be, Mg, Al, Ge, Si, Sn, Sb, Bi, Ti, Zr, Hf, V, Nb, Ta, and W, as well as alloys or compounds of at least one of these metals with other elements. The most well-known representatives of valve metals are Al, Ta, and Nb. Combinations of electrical properties equivalent to valve metals are those that have metallic conductivity, which can be oxidized and whose oxide layer provides the aforementioned properties. For example, NbO exhibits metallic conductivity but is not generally considered a valve metal. However, the layer of oxidized NbO exhibits the typical properties of valve metal oxide layers, making NbO or alloys or compounds of NbO with other elements typical examples of such compounds having electrical properties equivalent to valve metals. Electrode materials made of tantalum, aluminum, and such electrode materials based on niobium or niobium oxide are preferred. Tantalum is a particularly preferred electrode material.

[0152] To fabricate porous electrode bodies that often have porous regions, valve metal can be sintered in powder form to provide a generally porous electrode body, for example, or alternatively, the porous structure can be imprinted onto a metal body. The latter can be implemented, for example, by etching a film.

[0153] In the following text, for simplicity, a body having porous regions will also be referred to as porous. For example, an electrode body having porous regions will also be referred to as a porous electrode body. On the one hand, a porous body can be permeated by multiple channels and is therefore sponge-like. This is often the case when tantalum is used in the construction of a capacitor. On the other hand, pores can exist only at the surface, and the region disposed below the surface pores can be formed in a solid manner. This is often observed when aluminum is used in the construction of a capacitor.

[0154] The porous electrode body manufactured in this way is then oxidized by applying a voltage, for example, in an aqueous solution of a suitable electrolyte, such as phosphoric acid or ammonium adipate, to form a dielectric. The magnitude of this formation voltage depends on the thickness of the oxide layer to be achieved or, respectively, the subsequent operating voltage of the capacitor. Preferred formation voltages are in the range of 1V to 1000V, particularly preferably in the range of 10V to 200V, more preferably in the range of 15V to 100V, and even more preferably in the range of 20V to 50V.

[0155] The porous electrode body used preferably has a porosity of 10% to 90%, more preferably 30% to 80%, particularly preferably 50% to 80%, and an average pore size of 10 nm to 10000 nm, preferably 50 nm to 5000 nm, particularly preferably 100 nm to 3000 nm.

[0156] According to a specific embodiment of the method of the present invention, the electrolytic capacitor to be manufactured is an aluminum wound capacitor. In this case, in step A), a porous aluminum film as an electrode material is anoly formed, thereby forming an alumina coating as a dielectric. The aluminum film thus obtained (anode film) is then provided with contact lines and wound with another porous aluminum film (cathode film), which is also provided with contact lines, thereby separating the two films from each other by one or more sheets of separating paper, which are based on, for example, cellulose or preferably synthetic paper. After winding, the anode body obtained in this way is fixed, for example, by means of adhesive tape. The one or more sheets of separating paper can be carbonized by heating in an oven. This method of manufacturing the anode body of an aluminum wound capacitor is well known from the prior art and is described, for example, in US 7,497,879B2.

[0157] To form a solid electrolyte layer that at least partially covers the surface of the dielectric layer, a conductive polymer is chemically or electrochemically deposited on the dielectric, for example, by means of oxidative polymerization. For this purpose, a precursor for preparing the conductive polymer, one or more oxidants, and, if appropriate, counterions are applied together or sequentially to the dielectric of the porous electrode body and polymerized chemically and oxidatively, or by electrochemical polymerization, to polymerize the precursor for preparing the conductive polymer and the counterions on the dielectric of the porous electrode body.

[0158] Preferably, in order to form a solid electrolyte layer that at least partially covers the surface of the dielectric layer, a dispersion comprising a conductive polymer may be introduced into at least a portion of the provided porous electrode body, wherein the dispersant is subsequently removed to form a solid electrolyte that at least partially covers the surface of the dielectric layer.

[0159] Suitable conductive polymers for forming a solid electrolyte layer include polypyrrole, polythiophene, polyaniline, polyacetylene, polyphenylene, and poly(p-phenylene-vinylene), wherein polythiophene, especially those polythiophenes described above as preferred dispersions according to the invention, are preferred. The most preferred form for the formation of a solid electrolyte layer is a dispersion containing cationic polythiophene in the form of a polythiophene / polyanionic complex, or even more preferably in the form of a PEDOT / PSS complex, self-doped polythiophene such as poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxane-2-yl)methoxy]propane-1-sulfonic acid), poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxane-2-yl)methoxy]butane-1-sulfonic acid) (PEDOT-S) or poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxane-2-yl)methoxy]butane-2-sulfonic acid) or mixtures thereof.

[0160] Such a dispersion can be introduced into the porous region using known methods, such as immersion, impregnation, pouring, dripping, injection, spraying, spreading, brushing, or printing (e.g., inkjet printing, screen printing, or pad printing). This introduction is preferably carried out by immersing the porous electrode body in and thus impregnating it with the dispersion. Immersion in or impregnation with the dispersion is preferably carried out for a duration in the range of 1 second to 120 minutes, particularly preferably in the range of 10 seconds to 60 minutes, and most preferably in the range of 30 seconds to 15 minutes. The introduction of the dispersion into the anode body can be facilitated, for example, by increasing or decreasing pressure, vibration, ultrasound, or heat.

[0161] After the porous electrode body has been impregnated with the dispersion as described above, the dispersant is at least partially removed, resulting in the formation of a solid electrolyte layer that partially or completely covers the dielectric. In this context, it is preferred that the solid electrolyte layer covers at least 50% of the dielectric, particularly preferably at least 70%, and most preferably at least 80%, wherein the capacitance of the capacitor under dry and humid conditions at 120°C can be determined as described in DE-A-10 2005 043 828.

[0162] The removal of the dispersant is preferably carried out by removing the porous electrode body from the dispersion and then drying, wherein the drying is preferably carried out at a temperature in the range of 20°C to 200°C, particularly preferably in the range of 50°C to 180°C, and more preferably in the range of 80°C to 150°C. The drying conditions (i.e., drying time, drying pressure, and drying temperature) are preferably adjusted to ensure that at least 50% by weight, more preferably at least 75% by weight, even more preferably at least 90% by weight, even more preferably at least 95% by weight, and most preferably at least 99% by weight of the total amount of dispersant is removed when forming the solid electrolyte layer. In a particularly preferred embodiment of the method according to the invention, the drying conditions are adjusted to ensure that the dispersant is completely removed when forming the solid electrolyte layer.

[0163] Method steps B) and C):

[0164] In step B), a dispersion according to the invention, preferably a dispersion according to the invention as defined in any one of the first to eighteenth embodiments, or a dispersion obtainable by method 1 according to the invention, preferably by method 1 as defined in any one of the first to seventh embodiments, is applied to at least a portion of the surface of the solid electrolyte layer. Then, in step C), the dispersant i) is at least partially removed to form a polymer outer layer that at least partially covers the surface of the solid dielectric layer.

[0165] As used herein, the term "polymer outer layer" preferably refers to an outer layer that, although it may contain the exact same conductive polymer as the solid electrolyte layer, differs from the solid electrolyte layer in, for example, chemical composition, conductivity, and / or properties such as hardness, surface roughness, and adhesion. Typically, a polymer outer layer with a thickness ranging from 5 μm to 50 μm serves as a mechanical buffer between the anode and cathode side contacts of the capacitor, thereby preventing the cathode side contacts from contacting the dielectric under mechanical stress that may occur during capacitor manufacturing.

[0166] In step B), the application of the dispersion according to the invention to at least a portion of the surface of the solid electrolyte layer and the subsequent removal of the dispersant in step C) can be performed in the same manner as described above regarding the application of the dispersion for preparing the solid electrolyte layer.

[0167] Before applying the dispersion according to the invention to at least a portion of the surface of the solid electrolyte layer in step B), a crosslinking agent may advantageously be applied to at least a portion of the surface of the solid electrolyte layer to improve the coverage of the polymer outer layer on the capacitor anode. Suitable crosslinking agents and methods of application thereof are disclosed, for example, in DE 10 2009 007 594A1.

[0168] Encapsulation in method step D):

[0169] After the polymer outer layer is applied, the electrolytic capacitor can be finished, particularly encapsulated, in a manner known to those skilled in the art. In the case of a tantalum electrolytic capacitor, the capacitor body can be coated, for example, with a graphite and silver layer as known from DE-A-10 2005 043828, while in the case of an aluminum wound capacitor corresponding to the teachings of US 7,497,879 B2, the capacitor body is built into an aluminum cup provided with sealing rubber and mechanically securely closed by flange processing.

[0170] Encapsulation is preferably achieved by sealing the capacitor body with a resin (such as epoxy resin or thermoplastic resin, as disclosed in EP 0 447 165 A2). In the case of aluminum electrolytic capacitors, encapsulation is preferably achieved by providing an aluminum cup for the porous electrode body obtained in method step e) and closing the aluminum cup with sealing rubber.

[0171] The features disclosed in the claims, specification and drawings may be essential for different embodiments of the claimed invention, whether individually or in any combination of each other. Attached Figure Description

[0172] The following schematic diagrams illustrate aspects of the invention to improve the understanding of the invention in conjunction with some exemplary illustrations.

[0173] Figure 1 The structure of a layered body 100 prepared by the method for preparing a layered structure according to the present invention is shown in a general form, such as an antistatic film. In the case of an antistatic film that is typically a PE, PP, or PET layer, a conductive layer 102 prepared with the composition according to the present invention is placed on the substrate surface of the substrate 101.

[0174] Figure 2A schematic cross-sectional view is shown through a portion of a capacitor obtained by a specific embodiment of the method for preparing a layered structure according to the invention. The capacitor includes a porous electrode body 101a comprising pores 103, the porous electrode body being primarily made of a porous electrode material 101b, such as aluminum. On the surface of the electrode material 101b, a dielectric layer 101c is formed as a thin layer, such that an anode body, still porous, is formed, comprising the electrode body 101a made of the electrode material 101b and the dielectric layer 101c. On the dielectric layer 101c, optionally following other layers, is a layer of solid electrolyte 101d, such that a capacitor body is formed, comprising the electrode body 101a made of the electrode material 101b, the dielectric layer 101c, and the solid electrolyte layer 101d. The solid electrolyte layer 101d is at least partially covered by a polymer outer layer 102a (which is prepared using a dispersion according to the invention).

[0175] Measurement method:

[0176] Solid content

[0177] Weigh an empty weighing bottle (50 mm in diameter) with a cap using an analytical balance (weight A). Add approximately 5 g of the dispersion to the empty weighing bottle and weigh it with the cap on (weight B). Transfer the opened weighing bottle and cap separately to a drying oven and dry at 100°C for 15 to 16 hours.

[0178] After drying, seal the weighing bottle directly with the cap and cool to room temperature with the cap on. Then weigh the weighing bottle together with the cap on. (Weight C) Repeat the measurement a second time with a new sample.

[0179] The solid content is calculated using the following formula:

[0180] The weight percentage of solids is calculated as follows: (CA) × 100 / (BA).

[0181] Solid content measurements are performed as two separate measurements. The maximum allowable difference between these two solid content measurements is 0.03%. If the difference is large, the measurements must be repeated.

[0182] The final value is the average of two separate measurements.

[0183] electrical conductivity

[0184] To measure conductivity, 19 g of the dispersion to be analyzed was mixed with 1 g of DMSO in a flask and stirred for 10 minutes. Conductivity is the reciprocal of resistivity. Resistivity is calculated by multiplying the surface resistance of the conductive polymer layer by the layer thickness. The surface resistance of the conductive polymer was determined according to DIN EN ISO 3915. The mixture of polymer dispersion and DMSO was applied as a uniform film onto a thoroughly cleaned glass substrate measuring 50 mm × 50 mm using a spin coater. The coating composition was applied to the substrate using a pipette to completely cover the area and then directly peeled off by spin coating. The spin coating composition was rotated in air at approximately 1,000 rpm for 20 seconds. It was then dried on a hot plate (in air at 130°C for 15 minutes). A 2.0 cm long silver electrode was vapor-deposited onto the polymer layer at a distance of 2.0 cm using a shadow mask. The square area of ​​the layer between the electrodes was then electrically separated from the rest of the layer by drawing two lines with a scalpel. The surface resistance between the Ag electrodes was measured using an ohmmeter (Keithley 614). The thickness of the polymer layer at the crossed-out locations was determined using a stylus profilometer (Dektac 150, Veeco).

[0185] Particle count

[0186] The number of particles was measured using the Accusizer 780 SIS (PSS NICOMP, Particle Sizing Systems, Santa Barbara, California, USA) equipped with Accusizer 780 SIS software.

[0187] 7.5 g of the dispersion to be analyzed was diluted with 742.5 g of high-purity water. As a result, the concentration was diluted 100 times.

[0188] The experimental parameters are set as follows:

[0189] Injection volume: Large volume

[0190] Container quantity: 1

[0191] Number of draws: 10

[0192] Extraction volume: 10ml

[0193] Tare volume: 0ml

[0194] Infusion volume: 2ml

[0195] Does it include the first draw? Yes

[0196] Channel settings:

[0197]

[0198] During the measurement, the number of particles in a 10 × 10 ml diluted dispersion was measured. The number of particles >1.5 μm and the number of particles >10 μm were recorded. The total number of these 10 × 10 ml was reported as the number of particles per 1 ml of the original dispersion to be analyzed.

[0199] Particle size (d) 50 The determination of )

[0200] The particle size was determined as published by HG Müller in Colloid Polym. Sci. 267, 1113-1116 (1989). The diameter distribution d 50 The value indicates that 50% of the total weight of all conductive polymer particles in the dispersion can be attributed to particles with a diameter less than or equal to d. 50 - those particles with value.

[0201] Surface roughness

[0202] A 50mm × 50mm glass substrate was thoroughly cleaned and UV-ozone treated. The dispersion to be analyzed was applied as a homogeneous film using a spin coater. The coating composition was spin-coated in air at approximately 1,000 rpm for 20 seconds. It was then dried on a hot plate (in air at 130°C for 10 minutes). Surface roughness was measured using a stylus profilometer (Dektac 150, Veeco). A 5μm diameter stylus and a stylus force of 7μg were used to scan over a length of 1000μm at a scanning speed of 66.7μm / s. The surface roughness Rq is the root mean square value of the deviation from the profile height of the average line. Rq is defined according to ISO 4287:1998 + AC 2008.

[0203] Leakage current measurement

[0204] After applying 20V for 3 minutes, the leakage current (DCL) was determined using a Keithley 199 multimeter. The leakage current of the 5 capacitors was measured and the average leakage current (DCL) value was determined.

[0205] average value

[0206] Unless otherwise specified, the average corresponds to the arithmetic mean.

[0207] Example

[0208] Example 1

[0209] A 3L stainless steel reactor was used, equipped with a stirrer, vent, top material inlet, internal thermometer, ultra-turrax, bottom material outlet, and a temperature jacket connected to a thermostat. First, 2,186 g of deionized water and 102 g of polystyrene sulfonic acid aqueous solution (Mw 70,000 g / mol; solids content -25 wt%; total PSS solids 25.5 g) were added to the reactor. The reaction temperature was maintained at 10 °C throughout the reaction. The mixture was purged with nitrogen for 3 h. The mixture was then evacuated to 33 hPas. With the stirrer and ultra-turrax running, 10.2 g of 3,4-ethylenedioxythiophene (71.8 mmol) was added. The solution was mixed for 30 min. Subsequently, 0.06 g of ferric sulfate (III) and 19.0 g of sodium persulfate (79.8 mmol) dissolved in 50 g of water were added through the material inlet, and the solution was further stirred and dispersed under reduced pressure for 23 h.

[0210] After 23 hours, bring the reactor to atmospheric pressure. Transfer the dispersion to a 3L beaker. Remove inorganic salts by adding 290 ml of cation exchanger (Lewatit S108H, Lanxess AG) and 500 ml of anion exchanger (Lewatit MP 62, Lanxess Ag). Stir the mixture for 2 hours. Remove the ion exchange resin using a 400µm filter sieve (ED-Schnellsieb mittel400my; Drefi Drehkopf & FIDI GmbH; Germany). This dispersion is referred to as "Dispersion 1".

[0211] Dispersion 1 was filtered using a 125 μm filter sieve (ED-Schnellsieb super fein 125my; Drefi Drehkopf & FIDI GmbH; Germany). The resulting "Dispersion 1A" exhibited the following properties:

[0212] Solid content: 1.2% by weight

[0213] The dispersion 1A was then further filtered using a 10 μm filter (Pall DFA4001J100) at a pressure of 0.3 bar. The resulting stylus profilometer dispersion exhibited the following properties:

[0214] Electrical conductivity: 534 S / cm

[0215] 80 g of the dispersion filtered through a 10 μm filter, 3 g of sulfonyl polyester (Eastek 1100, Eastman), and 4 g of dimethyl sulfoxide were vigorously mixed in a glass beaker with a stirrer for 1 hour. The properties of the resulting "dispersion 1B" (according to the present invention) are summarized in Table 1.

[0216] Example 2

[0217] A dispersion identical to dispersion 1A was prepared. 300 g of the dispersion was filtered using a 4.5 μm filter (Pall DFA4001J045) at a pressure of 3 bar. The resulting "dispersion 2A" exhibited the following properties:

[0218] Electrical conductivity: 523 S / cm

[0219] 80 g of dispersion 2A, 3 g of sulfonyl polyester (Eastek 1100, Eastman) and 4 g of dimethyl sulfoxide were vigorously mixed in a glass beaker with a stirrer for 1 hour. The properties of "dispersion 2B" (according to the present invention) are summarized in Table 1.

[0220] Example 3

[0221] Place 300g of dispersion 1A in a beaker. Place the beaker in a water / ice bath. Add Ultra-Turrax (IKA T 25 basic) to the dispersion and stir at 6500rpm for 1 hour. Filter the resulting dispersion using a 4.5μm filter (Pall DFA4001J045) at a pressure of 1.5 bar. The resulting dispersion is referred to as "dispersion 3A".

[0222] 80 g of dispersion 3A, 3 g of sulfonyl polyester (Eastek 1100, Eastman) and 4 g of dimethyl sulfoxide were vigorously mixed in a glass beaker with a stirrer for 1 hour. The properties of "dispersion 3B" (according to the present invention) are summarized in Table 1.

[0223] Example 4

[0224] The same dispersion as dispersion 1A was prepared. 500 g of the dispersion was homogenized once using a high-pressure homogenizer operating at 1500 bar. The dispersion was then filtered using a 4.5 μm filter (Pall DFA4001J045) at a pressure of 1.0 bar. The resulting "dispersion 4A" exhibited the following properties:

[0225] Electrical conductivity: 530 S / cm

[0226] Mix 80g of dispersion 4A, 3g of sulfonated polyester (Eastek 1100, Eastman) and 4g of dimethyl sulfoxide in a glass beaker with a stirrer for 1 hour.

[0227] The properties of “Dispersion 4B” (not according to the present invention) are summarized in Table 1.

[0228] Example 5

[0229] Prepare a dispersion identical to dispersion 1A. Homogenize the dispersion 10 times using a high-pressure homogenizer operating at 1500 bar. Filter 2000 g of the dispersion using a 4.5 μm filter (Pall DFA4001J045) at a pressure of 1.0 bar. The resulting dispersion is referred to as "dispersion 5A".

[0230] 80 g of dispersion 5A, 3 g of sulfonyl polyester (Eastek 1100, Eastman) and 4 g of dimethyl sulfoxide were vigorously mixed in a glass beaker with a stirrer for 1 hour. The properties of "dispersion 5B" (not according to the invention) are summarized in Table 1.

[0231] Example 6

[0232] Prepare a dispersion identical to dispersion 1.

[0233] 80 g of the dispersion, 3 g of sulfonyl polyester (Eastek 1100, Eastman), and 4 g of dimethyl sulfoxide were vigorously mixed in a glass beaker with a stirrer for 1 hour. The properties of "Dispersion 6B" (not according to the invention) are summarized in Table 1.

[0234] Example 7

[0235] 44g of dispersion 5B was mixed with 6g of dispersion 6B. This mixture was referred to as "dispersion 7B". The properties of "dispersion 7B" (according to the present invention) are summarized in Table 1.

[0236] Example 8

[0237] 2.5 L of water was placed in a 5 L round-bottom flask equipped with a stirrer and thermometer. 214.2 g of p-toluenesulfonic acid monohydrate and 2.25 g of ferric toluenesulfonate (III) were added, and the mixture was stirred at room temperature for 30 minutes. Then, 85.8 g of ethylenedioxythiophene was added and stirred for 30 minutes. Subsequently, 192.9 g of sodium persulfate was added with stirring. The mixture was stirred at room temperature for another 24 hours. The resulting PEDOT / toluenesulfonate powder was collected on a porcelain suction filter and washed with 3 L of deionized water. The powder was then dried at 100 °C for 6 hours. 89 g of black PEDOT / p-toluenesulfonate powder was obtained.

[0238] Mix 1g of PEDOT / toluenesulfonate powder with 99g of dispersion 5A for 30 minutes.

[0239] 80 g of the dispersion, 3 g of sulfonyl polyester (Eastek 1100, Eastman), and 4 g of dimethyl sulfoxide were vigorously mixed in a glass beaker with a stirrer for 1 hour. This mixture was designated as dispersion 8B. The properties of "dispersion 8B" (not according to the invention) are summarized in Table 1.

[0240] Example 9

[0241] 0.25 g of the PEDOT / toluenesulfonate powder prepared as in Example 8 was mixed with 99.75 g of dispersion 1A for 30 minutes. 80 g of this dispersion, 3 g of sulfonated polyester (Eastek 1100, Eastman), and 4 g of dimethyl sulfoxide were then vigorously mixed in a glass beaker with a stirrer for 1 hour. This mixture was referred to as "dispersion 9B". The properties of "dispersion 9B" (not according to the invention) are summarized in Table 1.

[0242] Example 10

[0243] 46g of dispersion 5B and 4g of dispersion 6B were mixed. This mixture is called "dispersion 10B". The properties of "dispersion 10B" (according to the present invention) are summarized in Table 1.

[0244] Example 11

[0245] Prepare a dispersion identical to that of dispersion 1A. Filter 100g of the dispersion using a 25μm filter (Schwegmann Filtrations-Technik; 25μm polyamide monofilament).

[0246] 80g of the obtained dispersion, 3g of sulfonyl polyester (Eastek 1100, Eastman), and 4g of dimethyl sulfoxide were vigorously mixed in a glass beaker with a stirrer for 1 hour. This dispersion is referred to as "dispersion 11B". The properties of "dispersion 11B" (according to the present invention) are summarized in Table 1.

[0247] Example 12

[0248] 60g of dispersion 11B was mixed with 30g of dispersion 1B. This mixture is called "dispersion 12B". The properties of "dispersion 12B" (according to the present invention) are summarized in Table 1.

[0249] Example 13

[0250] Prepare 300 g of dispersion identical to dispersion 3A. Pass the dispersion through a 4.5 μm filter (Pall DFA4001J045) twice at a pressure of 1.4 bar. The resulting dispersion is referred to as "dispersion 13A".

[0251] 80 g of the obtained dispersion, 3 g of sulfonyl polyester (Eastek 1100, Eastman), and 4 g of dimethyl sulfoxide were vigorously mixed in a glass beaker with a stirrer for 1 hour. This dispersion is referred to as "Dispersion 13B". The properties of "Dispersion 13B" (according to the present invention) are summarized in Table 1.

[0252] Table 1 summarizes the results of Examples 1 through 13. :

[0253]

[0254] i = according to the present invention; ni = not according to the present invention

[0255] Example 14

[0256] Capacitor manufacturing methods

[0257] Method Step A):

[0258] Tantalum powder with a specific capacitance of 50,000 CV / g was pressed into microspheres containing tantalum wire and sintered to form a porous electrode body with dimensions of 1.5 mm × 2.9 mm × 4.0 mm. These porous electrode bodies were anodized in a 30 V phosphoric acid electrolyte to form a dielectric, thereby obtaining a capacitor body.

[0259] The capacitor body of the method step was immersed in an aqueous solution of poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (Clevios K Nano LV, Heraeus Deutschland) for 1 minute. Then, it was dried at 120°C for 10 minutes. This process of immersion and drying was repeated nine times to obtain a PEDOT / PSS-based solid electrolyte layer.

[0260] Method steps B) and C):

[0261] The outer polymer layer on the capacitor body is obtained through steps B) and C). In step B), the capacitor body from step A) is immersed in a crosslinking agent solution (Clevios K Primer W15, Heraeus Deutschland). Then, it is dried at 120°C for 10 minutes. Subsequently, the capacitor body is immersed in dispersion 1B of Example 1. Afterwards, in step C), it is dried at 120°C for 10 minutes.

[0262] The capacitor body of step C) is then covered with a graphite layer, and then covered with a silver layer to obtain the finished capacitor in this way.

[0263] Table 2 shows the average leakage current of the capacitors (according to the present invention).

[0264] Example 15

[0265] The capacitors were produced and evaluated in the same manner as in Example 14; however, in step B), dispersion 2B of Example 2 was used instead of dispersion 1B of Example 1. The average leakage current of the capacitors (according to the present invention) is given in Table 2.

[0266] Example 16

[0267] The capacitors were produced and evaluated in the same manner as in Example 14; however, in step B), dispersion 3B of Example 3 was used instead of dispersion 1B of Example 1. The average leakage current of the capacitors (according to the present invention) is given in Table 2.

[0268] Example 17

[0269] The capacitors were produced and evaluated in the same manner as in Example 14; however, in step B), dispersion 4B of Example 4 was used instead of dispersion 1B of Example 1. The average leakage current of the capacitors (not according to the present invention) is given in Table 2.

[0270] Example 18

[0271] The capacitors were produced and evaluated in the same manner as in Example 14; however, in step B), dispersion 5B of Example 5 was used instead of dispersion 1B of Example 1. The average leakage current of the capacitors (not according to the present invention) is given in Table 2.

[0272] Example 19

[0273] The capacitors were produced and evaluated in the same manner as in Example 14; however, in step B), dispersion 6B of Example 6 was used instead of dispersion 1B of Example 1. The average leakage current of the capacitors (not according to the present invention) is given in Table 2.

[0274] Example 20

[0275] The capacitors were produced and evaluated in the same manner as in Example 14; however, in step B), dispersion 7B of Example 7 was used instead of dispersion 1B of Example 1. The average leakage current of the capacitors (according to the present invention) is given in Table 2.

[0276] Example 21

[0277] The capacitors were produced and evaluated in the same manner as in Example 14; however, in step B), dispersion 8B of Example 8 was used instead of dispersion 1B of Example 1. The average leakage current of the capacitors (not according to the present invention) is given in Table 2.

[0278] Example 22

[0279] The capacitors were produced and evaluated in the same manner as in Example 14; however, in step B), dispersion 9B of Example 9 was used instead of dispersion 1B of Example 1. The average leakage current of the capacitors (not according to the present invention) is given in Table 2.

[0280] Example 23

[0281] The capacitors were produced and evaluated in the same manner as in Example 14; however, in step B), dispersion 10B of Example 10 was used instead of dispersion 1B of Example 1. The average leakage current of the capacitors (according to the present invention) is given in Table 2.

[0282] Example 24

[0283] The capacitors were produced and evaluated in the same manner as in Example 14; however, in step B), dispersion 11B of Example 11 was used instead of dispersion 1B of Example 1. The average leakage current of the capacitors (according to the present invention) is given in Table 2.

[0284] Example 25

[0285] The capacitors were produced and evaluated in the same manner as in Example 14; however, in step B), dispersion 12B of Example 12 was used instead of dispersion 1B of Example 1. The average leakage current of the capacitors (according to the present invention) is given in Table 2.

[0286] Example 26

[0287] The capacitors were produced and evaluated in the same manner as in Example 14; however, in step B), dispersion 13B of Example 13 was used instead of dispersion 1B of Example 1. The average leakage current of the capacitors (according to the present invention) is given in Table 2.

[0288] Table 2 summarizes the results of Examples 9 through 16. :

[0289]

[0290] i = according to the present invention; ni = not according to the present invention

[0291] Reference number index

[0292] 100 layers

[0293] 101 substrate

[0294] 101a porous electrode body

[0295] 101b electrode material

[0296] 101c dielectric

[0297] 101d solid electrolyte layer

[0298] 102 conductive layer

[0299] 102a polymer outer layer

[0300] 103 pores

Claims

1. A dispersion comprising: i) Dispersant; ii) At least one polythiophene dispersed in the dispersant i); The dispersion comprises particles with a particle size of 1.5 μm or larger, and the total number of these particles is in the range of 20,000 / ml to 1,000,000 / ml; and The surface roughness Rq of the conductive layer prepared from the dispersion is in the range of 4 nm to 23 nm.

2. The dispersion according to claim 1, The dispersion comprises 100,000 to 900,000 particles per milliliter, the particles having a particle size of 1.5 μm or larger; and The surface roughness Rq of the conductive layer prepared from the dispersion is in the range of 4 nm to 10 nm.

3. The dispersion according to claim 1 or 2, wherein the dispersion comprises more than 1,500 particles per milliliter, the particles having a particle size of 10 μm or larger.

4. The dispersion according to any one of claims 1 to 3, wherein the dispersant i) comprises water.

5. The dispersion according to any one of claims 1 to 4, wherein the polythiophene exists in the form of particles comprising a complex of the polythiophene and a polyanion.

6. The dispersion according to claim 5, wherein the polythiophene is poly(3,4-ethylenedioxythiophene), and wherein the polyanion is an anion of polystyrene sulfonic acid.

7. The dispersion according to claim 5 or 6, wherein the weight-average diameter (d) of the particles comprising the complex of polythiophene and polyanion is... 50 (In the range of 10nm to 500nm) 8. The dispersion according to any one of claims 1 to 7, wherein the conductivity of the conductive layer prepared from said dispersion is at least 10 S / cm, as determined by the test methods disclosed herein.

9. The dispersion according to any one of claims 1 to 8, wherein the polythiophene exists in the form of particles comprising a complex of the polythiophene and a polyanion, and wherein the number and size of the particles as defined in claims 1, 2 and 3 refer to the number and size of the particles comprising the complex of the polythiophene and the polyanion.

10. The dispersion according to any one of claims 1 to 8, wherein the dispersion has a solid content of at least 1% by weight based on the total weight of the dispersion.

11. A method for preparing a layered body (100), the method comprising the following steps: A) Provide a substrate (101); B) Applying the dispersion according to any one of claims 1 to 10 to at least a portion of the surface of the substrate (101); C) At least partially remove the dispersant i) to obtain a layer (100) comprising a conductive layer (102) coated on at least a portion of the surface of the substrate (101).

12. The method of claim 11, wherein the layered body (100) is part of a solid electrolyte capacitor, wherein the substrate (101) is a porous electrode body (101a) made of electrode material (101b), wherein a dielectric layer (101c) at least partially covers the surface of the electrode material (101b), wherein a solid electrolyte layer (101d) at least partially covers the surface of the dielectric layer (101c), and wherein the conductive layer (102) is a polymer outer layer (102a) that at least partially covers the surface of the solid electrolyte layer (101d).

13. The method of claim 12, wherein the method comprises the following steps: A) Provides a porous electrode body (101a) made of electrode material (101b), wherein a dielectric layer (101c) at least partially covers the surface of the electrode material (101b), and wherein a solid electrolyte layer (101d) at least partially covers the surface of the dielectric layer (101c); B) Applying the dispersion according to any one of claims 1 to 10 to at least a portion of the solid electrolyte layer (101d); C) At least partially remove the dispersant i) to form a polymer outer layer (102a) that at least partially covers the surface of the solid electrolyte layer (101d).

14. A layered body that can be obtained by the method according to any one of claims 11 to 13.

15. Use of the dispersion according to any one of claims 1 to 10 for forming a polymeric outer layer in a capacitor.

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