Solid electrolytic capacitor with conductive polymer layer having excellent resistance to metal ion migration

Abstract

The present invention relates to a capacitor comprising i) an electrode body comprising an electrode material, wherein a dielectric layer comprising a dielectric material at least partially covers the surface of the electrode body; ii) a solid electrolyte layer comprising a solid electrolyte material at least partially covering the surface of the dielectric layer, wherein the solid electrolyte material comprises a conductive polymer; iii) an anode contact in contact with the electrode body and comprising copper, metal-plated copper or a copper-containing alloy; and iv) a cathode contact in contact with the solid electrolyte layer; wherein the capacitor further comprises at least one metal ion migration inhibitor. The present invention also relates to a method for producing a capacitor, to a capacitor obtainable by such a method, to an electronic circuit comprising a capacitor according to the present invention, and to the use of these capacitors in electronic circuits.

Description

[0001] The present invention relates to a capacitor comprising i) an electrode body comprising an electrode material, wherein a dielectric layer comprising a dielectric material at least partially covers the surface of the electrode body, ii) a solid electrolyte layer comprising a solid electrolyte material at least partially covering the surface of the dielectric layer, wherein the solid electrolyte material comprises a conductive polymer, iii) an anode contact in contact with the electrode body and comprising copper, metallized copper or a copper-containing alloy and iv) a cathode contact in contact with the solid electrolyte layer. The present invention also relates to a method for producing a capacitor, to a capacitor obtainable by such a method, to an electronic circuit comprising a capacitor according to the present invention, and to the use of these capacitors in electronic circuits.

[0002] Most electronic circuits contain capacitors. These devices store and release charge in response to circuit current, producing predictable voltage increases and decreases across them. It is this predictable and limited short-term variation in terminal voltage that makes capacitors useful, for example, as decoupling and filtering devices in electronic circuits. Specifically, capacitors are useful in circuit locations where we do not want rapid voltage changes. One excellent use of capacitors is to minimize or "filter out" random and periodic fluctuations from the output stage of a direct current (DC) power supply.

[0003] An example of a typical capacitor is a tantalum capacitor, which, like any other electrolytic capacitor, comprises an anode, some electrolyte material and a cathode. The anode is separated from the cathode, so only a very small leakage DC current can flow through the capacitor. The anode is made of pure tantalum metal. The metal is used in fine powder form and sintered into agglomerates at high temperatures. This forms a very porous electrode body with a high surface area. The high surface area directly translates into an increased capacitance value. The electrode body is then covered with an insulating oxide layer that acts as a dielectric material. This process is called anodization. In the case of a solid tantalum capacitor, a solid electrolyte material is then added to the anode by pyrolysis (in the case of manganese dioxide) or by impregnating the porous anode with a solution or dispersion containing a conductive polymer, such as a composite of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonic acid, or a monomer containing a conductive polymer, such as 3,4-ethylenedioxythiophene, which is then polymerized in situ in the electrode body to form a cathode. After the agglomerates used in solid tantalum capacitors are impregnated in carbon and silver to provide a good cathode connection, the anode (usually via a tantalum wire that has been inserted into the electrode body) and the cathode (via a silver layer) are connected to anode and cathode contacts (e.g., lead frames), via which the capacitor is connected to corresponding contacts integrated into the electronic device. Multilayer aluminum capacitors are another example of a typical solid electrolyte capacitor. They have a similar construction to tantalum capacitors, the main difference being the use of porous aluminum foil instead of an electrode body based on sintered tantalum powder, which is usually in direct contact with the anode lead frame.

[0004] Typically, an anode lead frame comprising copper as the conductive material is used. Since the anode lead frame in a common tantalum capacitor or a multilayer aluminum capacitor is usually positioned close to the solid electrolyte (such as in Figure 1 and 3 ), so especially in the case of a capacitor comprising a conductive polymer as a solid electrolyte material, problems may arise if, for example, moisture penetrates the space between the copper lead frame and the solid electrolyte when the capacitor is stored or operated in a humid environment. Conductive polymers such as PEDOT / PSS generally contain a large amount of ionic species such as H + 、Na + and SO4 2- , which migrates to a certain extent into the moisture-containing space between the copper lead frame and the solid electrolyte, which in turn causes the formation of a "conductive bridge" between these structures. If an electric field is applied between the anode and the cathode under these conditions, the copper ions tend to migrate from the anode lead frame to the solid electrolyte, where they are reduced and thus deposited under the formation of continuously growing copper dendrites. The accumulation of copper dendrites in the cathode region ultimately increases the risk of short circuits in the capacitor.

[0005] One approach to avoid ion migration in electronic devices is to reduce the ion content in the conductive polymer layer, as disclosed, for example, in JP 2017 / 063158A1. As stated above, conductive polymer layers such as PEDOT / PSS typically contain a large amount of ionic species, such as H + 、Na + and SO4 2- Although these ionic impurities can be at least partially extracted by washing the layers with water, a disadvantage in the case of PEDOT / PSS layers is that these layers swell upon contact with water, which in turn significantly affects the precise dimensions of the solid electrolyte layer and therefore also the electrical properties of the capacitor.

[0006] The invention is based on the object of overcoming the disadvantages resulting from the prior art relating to capacitors, in particular to solid electrolyte capacitors, very preferably to tantalum capacitors and aluminum capacitors, even more preferably to tantalum capacitors known from the prior art, which capacitors comprise a polythiophene-containing solid electrolyte layer and an anode contact based on copper, metallized copper or a copper-containing alloy.

[0007] In particular, the present invention is based on the object of providing a solid electrolyte capacitor, very preferably a tantalum capacitor or an aluminum capacitor, even more preferably a tantalum capacitor comprising a polythiophene-containing solid electrolyte layer and an anode contact based on copper, metallized copper or a copper-containing alloy, wherein this capacitor is characterized by a reduced risk of short-circuiting after operation in a humid atmosphere.

[0008] The present invention is also based on the object of providing a method for producing a solid electrolyte capacitor, the solid electrolyte layer of which comprises polythiophene, wherein it is not necessary to reduce the solid electrolyte layer in an additional method step. + 、Na + or SO4 2- The ion content.

[0009] The independent technical solutions contribute to at least partially solving at least one, preferably more than one, of the above objects. The dependent technical solutions provide preferred embodiments that contribute to at least partially solving at least one of the objects.

[0010] Embodiment 1 of a capacitor 1 contributes to solving at least one of the objects according to the invention, said capacitor comprising

[0011] i) an electrode body comprising an electrode material, wherein a dielectric layer comprising a dielectric material at least partially covers a surface of the electrode body;

[0012] ii) a solid electrolyte layer comprising a solid electrolyte material at least partially covering a surface of the dielectric layer, wherein the solid electrolyte material comprises a conductive polymer;

[0013] iii) an anode contact, preferably an anode lead frame, in contact with the electrode body, preferably in conductive contact and comprising copper, metallized copper or a copper-containing alloy; and

[0014] iv) a cathode contact in contact with the solid electrolyte layer, preferably in conductive contact, preferably a cathode lead frame;

[0015] Wherein the capacitor further comprises at least one metal ion migration inhibitor.

[0016] In the expression "solid electrolyte material at least partially covering the surface of the dielectric layer", the term "covering" must be understood in its broadest sense and in particular in such a way that the solid electrolyte layer is not necessarily in direct contact with at least a portion of the dielectric layer, but can also be separated from the dielectric layer by an intermediate layer, such as a layer comprising an adhesion promoter. Suitable adhesion promoters are silanes, such as organofunctional silanes or their hydrolysis products, for example 3-glycidyloxypropyltrialkoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane or octyltriethoxysilane, and / or one or more other functional layers applied to the dielectric layer of the electrical body.

[0017] In the expressions "anode contact in contact with the electrode body, preferably in conductive contact" and "cathode contact in contact with the solid electrolyte layer, preferably in conductive contact", the term "in contact with" must also be understood in its broadest sense and in particular in such a way that the anode contact and the cathode contact do not necessarily have to be in direct contact with the electrode body and the solid electrolyte layer, respectively. Other electrically conductive elements may be positioned between the anode contact and the electrode body and / or between the cathode contact and the solid electrolyte layer. For example, there may be an anode wire between the anode contact and the electrode body and / or there may be a graphite and / or Ag layer between the cathode contact and the solid electrolyte layer.

[0018] In embodiment 2 of the capacitor 1 according to the invention, the capacitor 1 is designed according to embodiment 1 thereof, wherein at least one metal ion migration inhibitor is located in the region between at least the anode contact and the solid electrolyte layer or in the solid electrolyte layer.

[0019] In embodiment 3 of the capacitor 1 according to the invention, the capacitor 1 is designed according to embodiment 1 or 2 thereof, wherein the capacitor is a tantalum capacitor. Preferably, such a tantalum capacitor contains tantalum as electrode material and contains tantalum oxide as dielectric material.

[0020] In a fourth embodiment of the capacitor 1 according to the present invention, the capacitor 1 is designed according to its third embodiment, wherein the capacitor further comprises the following additional components:

[0021] v) contact with an electrode material, preferably a tantalum wire or ribbon in conductive contact;

[0022] vi) an optional first conductive layer in contact, preferably electrically conductive contact, with the solid electrolyte layer, wherein the first conductive layer is preferably a carbon layer;

[0023] vii) a second conductive layer in contact, preferably in conductive contact, with the solid electrolyte layer or the first conductive layer, wherein the second conductive layer is a metal layer, preferably a silver layer;

[0024] viii) an optional insulating layer positioned on at least a portion of the surface of the tantalum wire or ribbon and by which conductive contact between the tantalum wire or ribbon and the solid electrolyte layer, the first conductive layer, and the second conductive layer is avoided;

[0025] ix) an optional cover layer covering at least a portion of the region between the anode contact and the solid electrolyte layer.

[0026] In embodiment 5 of the capacitor 1 according to the invention, the capacitor 1 is designed according to embodiment 4 thereof, wherein at least one metal ion migration inhibitor is positioned at a portion of at least one, preferably two or more of the following positions:

[0027] - on the surface of the anode contact;

[0028] - on the surface of the dielectric layer covering the electrode body;

[0029] - on the surface of the covering layer;

[0030] - on the surface of tantalum wire or ribbon;

[0031] - on the surface of the insulating layer or within the insulating layer;

[0032] - on a surface of the first conductive layer facing the solid electrolyte layer or on a surface of the first conductive layer facing away from the solid electrolyte layer;

[0033] on a surface of the second conductive layer facing the first conductive layer or on a surface of the second conductive layer facing away from the first conductive layer;

[0034] - on the surface of the solid electrolyte layer and / or within the solid electrolyte layer;

[0035] - within the first conductive layer;

[0036] - within the second conductive layer.

[0037] In embodiment 6 of the capacitor 1 according to the present invention, the capacitor 1 is designed according to embodiment 1 or 2 thereof, wherein the capacitor is an aluminum capacitor, preferably a multilayer aluminum capacitor comprising one aluminum sheet or a plurality of stacked sheets. Preferably, such an aluminum capacitor comprises aluminum as electrode material and aluminum oxide as dielectric material.

[0038] In embodiment 7 of the capacitor 1 according to the present invention, the capacitor 1 is designed according to embodiment 6 thereof, wherein the capacitor further comprises the following additional components:

[0039] v) an optional first conductive layer in contact, preferably electrically conductive contact, with the solid electrolyte layer, wherein the first conductive layer is preferably a carbon layer;

[0040] vi) a second conductive layer in contact, preferably in conductive contact, with the solid electrolyte layer or the first conductive layer, wherein the second conductive layer is a metal layer, preferably a silver layer;

[0041] vii) an optional insulating layer positioned on at least a portion of the surface of the electrode body or on a portion of the dielectric layer by which electrically conductive contact between the electrode body and the solid electrolyte layer, the first conductive layer and the second conductive layer is avoided;

[0042] viii) an optional cover layer covering at least a portion of the region between the anode contact and the solid electrolyte layer.

[0043] In embodiment 8 of the capacitor 1 according to the invention, the capacitor 1 is designed according to embodiment 7 thereof, wherein at least one metal ion migration inhibitor is positioned at a portion of at least one, preferably two or more of the following positions:

[0044] - on the surface of the anode contact;

[0045] - on the surface of the dielectric layer covering the electrode body;

[0046] - on the surface of the electrode body;

[0047] - on the surface of the covering layer;

[0048] - on the surface of the insulating layer or within the insulating layer;

[0049] - on a surface of the first conductive layer facing the solid electrolyte layer or on a surface of the first conductive layer facing away from the solid electrolyte layer;

[0050] on a surface of the second conductive layer facing the first conductive layer or on a surface of the second conductive layer facing away from the first conductive layer;

[0051] - on the surface of the solid electrolyte layer and / or within the solid electrolyte layer;

[0052] - within the first conductive layer;

[0053] - within the second conductive layer.

[0054] In embodiment 9 of capacitor 1 according to the present invention, capacitor 1 is designed according to any one of its embodiments 1 to 8, wherein at least one metal ion migration inhibitor is positioned on at least a portion of the surface of the solid electrolyte layer and / or positioned within at least a portion of the solid electrolyte layer.

[0055] In embodiment 10 of the capacitor 1 according to the present invention, the capacitor 1 is designed according to any one of its embodiments 1 to 9, wherein the solid electrolyte layer includes a first solid electrolyte layer after the dielectric layer and a second solid electrolyte layer after the first solid electrolyte layer, wherein the first solid electrolyte layer and the second solid electrolyte layer both contain a conductive polymer as a solid electrolyte material.

[0056] In embodiment 11 of the capacitor 1 according to the invention, the capacitor 1 is designed according to its embodiment 10, wherein at least one of the following conditions is satisfied:

[0057] a) at least one metal ion migration inhibitor is positioned within at least a portion of the first solid electrolyte layer;

[0058] b) at least one metal ion migration inhibitor is positioned within at least a portion of the second solid electrolyte layer;

[0059] c) at least one metal ion migration inhibitor is positioned on at least a portion of a surface of the first solid electrolyte layer that faces the second solid electrolyte layer;

[0060] d) at least one metal ion migration inhibitor is positioned on at least a portion of a surface of the second solid electrolyte layer facing away from the first solid electrolyte layer;

[0061] e) at least one metal ion migration inhibitor is positioned on at least a portion of the surface of the dielectric layer.

[0062] In an embodiment 12 of the capacitor 1 according to the invention, the capacitor 1 is designed according to any one of its embodiments 1 to 11, wherein the conductive polymer comprises polythiophene.

[0063] In embodiment 13 of the capacitor 1 according to the present invention, the capacitor 1 is designed according to embodiment 12 thereof, wherein the polythiophene is an externally doped polythiophene, preferably a cationic polythiophene in the form of a polythiophene / polyanion complex; a self-doped polythiophene or a mixture thereof. Preferably, the conductive polymer comprises a composite of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonic acid (PEDOT / PSS), poly(4-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]propane-1-sulfonic acid), poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)methoxy]butane-1-sulfonic acid) (PEDOT-S), poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)methoxy]butane-2-sulfonic acid) or a mixture thereof.

[0064] In embodiment 14 of the capacitor 1 according to the invention, the capacitor 1 is designed according to any one of its embodiments 1 to 13, wherein at least one metal ion migration inhibitor is selected from the group consisting of azoles or derivatives thereof, oxazines or derivatives thereof and amines.

[0065] In embodiment 15 of the capacitor 1 according to the present invention, the capacitor 1 is designed according to embodiment 14 thereof, wherein the azole is selected from the group consisting of: 4-methylimidazole, 4-methyl-5-imidazole-carboxaldehyde, ethyl-4-methyl-imidazole carboxylate, 4-methyl-1 (4-methoxy-phenyl) imidazole, benzimidazole, (mercaptobenzimidazole) pyrazole, 2-undecyl imidazole, poly-N-vinylimidazole, 1,2,3-triazole, 1,2,4-triazole, 5-methyl-1H-benzotriazole, tetrazole, pentazole, oxazole, isoxazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, oxadiazole, thiazole, isothiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 2-amino-5-ethylthio-1,3,4-thiadiazole, 2-amino-5-ethyl-1,3,4-thiadiazole, 3-amino-5-methyl-thio-1,2,4-triazole, 1-(p-tolyl)-4-methylimidazole, 1-phenyl-4-methylimidazole, 4-methyl-5-hydroxymethylimidazole, (2-mercapto-1-methylimidazole), 5-mercapto-1-phenyl-1H-tetrazole, 2-(3,5-di-tert-butyl-2-hydroxyphenyl)benzotriazole and derivatives of these azoles.

[0066] In embodiment 16 of the capacitor 1 according to the invention, the capacitor 1 is designed according to embodiment 15 thereof, wherein the azole is selected from the group consisting of 1,2,4-triazole, 5-methyl-1H-benzotriazole and derivatives or mixtures thereof.

[0067] In embodiment 17 of the capacitor 1 according to the invention, the capacitor 1 is designed according to embodiment 16 thereof, wherein the azole is 5-methyl-1H-benzotriazole or a derivative thereof.

[0068] In embodiment 18 of capacitor 1 according to the present invention, capacitor 1 is designed according to its embodiment 14, wherein the azole is selected from the group consisting of: bismuth reagent (bismuthiol) (1,5-dimercapto-1,3,4-thiadiazole), benzoxazole, 2-ethyl-4-methylimidazole, 1-allylimidazole, 4-methyl-2-phenylimidazole, 1-propylimidazole and derivatives of these azoles, preferably selected from the group consisting of: bismuth reagent, benzoxazole and 4-methyl-2-phenylimidazole.

[0069] In embodiment 19 of the capacitor 1 according to the invention, the capacitor 1 is designed according to embodiment 14 thereof, wherein the azine is selected from the group consisting of aromatic hydrazines, oxines, pyridines, pyridazines, pyrimidines, pyrazines, triazinones, tetrazines and derivatives of these azines.

[0070] In embodiment 20 of capacitor 1 according to the present invention, capacitor 1 is designed according to embodiment 19 thereof, wherein the azine is selected from the group consisting of: pyrazine-2,3-dicarboxamide, pyridine-2-amine, 3-amino-pyrazine 2-carboxylic acid, pyridine-2,3-diamine, pyrazine-2-amine, 2-(3-phenyl-4,5-dihydro-1H-pyrazol-5-yl)pyridine, 2-(3-phenyl-4,5-dihydro-1,2-oxazol-5-yl)-pyridine and 1,2-bis(4-chloro-benzylidene)oxazine.

[0071] In embodiment 21 of capacitor 1 according to the present invention, capacitor 1 is designed according to its embodiment 19, wherein the oxazine is selected from the group consisting of: 2-methyl-8-hydroxyquinoline, allopurinol (1H-pyrazolo[3,4-d]pyrimidin-4-one), 2-amino-5-methylpyridine, benzoguanamine, 2,3-dimethylpyrazine, thiocyanic acid and derivatives of these oxazines, preferably selected from the group consisting of: allopurinol, benzoguanamine, 2,3-dimethylpyrazine and thiocyanic acid.

[0072] In embodiment 22 of capacitor 1 according to the present invention, capacitor 1 is designed according to embodiment 14 thereof, wherein the amine is selected from the group consisting of ethanolamine, ethylamine, butylamine, isopropylamine, triethanolamine, aniline, benzylamine, octylamine, 2-ethylhexylamine, (N-(2-furylmethyl)-p-toluidine), (N-(5-chloro-2-furylmethyl)-p-toluidine), (N-(5-bromo-2-furylmethyl)-p-toluidine), (N-(5-nitro-2-furylmethyl)-p-toluidine), (N-(5-methyl-2-furylmethyl)-p-toluidine), N-methyl-p-toluidine, 2-(3-methoxyphenyl)ethylamine and 2-ethylhexylamine.

[0073] In embodiment 23 of the capacitor 1 according to the invention, the capacitor 1 is designed according to any one of its embodiments 1 to 22, wherein the amount of the metal ion migration inhibitor in the capacitor is 1 ppm to 10%, preferably 5 ppm to 1%, more preferably 10 ppm to 0.1%, in each case based on the total weight of the capacitor. The amount of the metal ion migration inhibitor in the solid electrolyte layer, preferably at least in the second solid electrolyte layer, is preferably in the range of 0.05% to 90%, preferably 1% to 75%, more preferably in the range of 5% to 50%, in each case based on the weight of the solid electrolyte layer, preferably the weight of the second solid electrolyte layer.

[0074] In embodiment 24 of the capacitor 1 according to the invention, the capacitor 1 is designed according to any one of its embodiments 1 to 23, wherein the metallized copper is selected from the group consisting of:

[0075] -Cu / Ni[Cu plated with Ni]

[0076] -Cu / Ni / Pd[Cu / Ni plated with Pd]

[0077] -Cu / Ni / Pd / Au[Au-plated Cu / Ni / Pd]

[0078] -Cu / Ni / Au[Au-plated Cu / Ni]

[0079] -Cu / Au[Au-plated Cu]

[0080] -Cu / Pd[Cu plated with Pd]

[0081] -Cu / Ni / Sn[Cu / Ni plated with Sn]

[0082] -Cu / Ni-Sn[Cu plated with Ni-Sn alloy]

[0083] -Cu / Sn[Cu plated with Sn]

[0084] -Cu / (Ni / )Cu-Sn [Cu-plated Cu-Sn alloy].

[0085] In embodiment 25 of the capacitor 1 according to the invention, the capacitor 1 is designed according to any one of embodiments 1 to 24 thereof, wherein the copper alloy is selected from the group consisting of Cu—Sn—P, Cu—Ni—Sn and Cu—Sn—Ni—Zn.

[0086] Embodiment 1 of a method for producing an object, preferably a capacitor, more preferably a capacitor 1 according to the invention, contributes to solving at least one of the objects according to the invention, said method comprising the method steps:

[0087] 1) providing an electrode body comprising an electrode material, wherein a dielectric comprising a dielectric material at least partially covers a surface of the electrode material;

[0088] II) depositing a solid electrolyte layer comprising a solid electrolyte material onto at least a portion of the surface of the dielectric layer, wherein the solid electrolyte material comprises a conductive polymer;

[0089] III) contacting the electrode body, preferably in conductive contact, to an anode contact comprising copper, plated copper or a copper-containing alloy, preferably to an anode lead frame; and

[0090] IV) contacting the solid electrolyte layer to a cathode contact, preferably to a cathode lead frame, preferably in conductive contact;

[0091] At least one metal ion migration inhibitor is introduced into the capacitor.

[0092] The expression "a solid electrolyte layer comprising a solid electrolyte material is deposited onto at least a portion of the surface of the dielectric layer" must be understood in its broadest sense and in particular in such a way that the solid electrolyte layer does not necessarily have to be deposited directly onto at least a portion of the dielectric layer, but can also be deposited onto an intermediate layer, such as a layer comprising an adhesion promoter, which has previously been applied to the dielectric layer. Suitable adhesion promoters are likewise silanes, such as organofunctional silanes or their hydrolysis products, for example 3-glycidyloxypropyltrialkoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane or octyltriethoxysilane, and / or one or more further functional layers are applied to the dielectric layer of the electrical body.

[0093] The expressions "the electrode body is brought into contact with the anode contact, preferably in electrically conductive contact" and "the solid electrolyte layer is brought into contact with the cathode contact, preferably in electrically conductive contact" must also be understood in their broadest sense and in particular in such a way that it is not necessarily necessary for the anode contact and the cathode contact to be in direct contact with the electrode body and the solid electrolyte layer, respectively. Other electrically conductive elements may be positioned between the anode contact and the electrode body and / or between the cathode contact and the solid electrolyte layer. For example, an anode wire may be present between the anode contact and the electrode body and / or a graphite and / or Ag layer may be present between the cathode contact and the solid electrolyte layer.

[0094] In embodiment 2 of method 1 according to the invention, method 1 is designed according to embodiment 1 thereof, wherein at least one metal ion migration inhibitor is introduced into the region between anode contact and solid electrolyte layer or into the solid electrolyte layer.

[0095] In embodiment 3 of method 1 according to the present invention, method 1 is designed according to embodiment 1 or 2 thereof, wherein the capacitor is a tantalum capacitor.

[0096] In embodiment 4 of method 1 according to the invention, method 1 is designed according to embodiment 3 thereof, wherein in method step I) the tantalum powder is sintered to obtain a porous electrode body.

[0097] In embodiment 5 of method 1 according to the present invention, method 1 is designed according to any one of embodiments 2 to 4 thereof, wherein the method comprises at least one of the following method steps:

[0098] V) providing an electrode body comprising a tantalum wire or ribbon extending out of the electrode body;

[0099] VI) optionally applying a first conductive layer to at least a portion of the solid electrolyte layer, wherein the first conductive layer is preferably a carbon layer;

[0100] VII) applying a second conductive layer onto at least a portion of the solid electrolyte layer or onto at least a portion of the first conductive layer, wherein the second conductive layer is a metal layer, preferably a silver layer;

[0101] VIII) optionally applying an insulating layer to at least a portion of the surface of the tantalum wire or tape in such a way that electrically conductive contact between the tantalum wire or tape and the solid electrolyte layer, the first conductive layer and the second conductive layer is avoided;

[0102] IX) Optionally applying a cover layer to at least a portion of the area between the anode contact and the solid electrolyte layer.

[0103] In embodiment 6 of method 1 according to the present invention, method 1 is designed according to embodiment 5 thereof, wherein at least one metal ion migration inhibitor is applied at least at one, preferably a part of two or more of the following locations:

[0104] - on the surface of the anode contact;

[0105] - on the surface of the dielectric layer covering the electrode body;

[0106] - on the surface of the covering layer;

[0107] - on the surface of tantalum wire or ribbon;

[0108] - on the surface of the insulating layer or within the insulating layer;

[0109] - on a surface of the first conductive layer facing the solid electrolyte layer or on a surface of the first conductive layer facing away from the solid electrolyte layer;

[0110] on a surface of the second conductive layer facing the first conductive layer or on a surface of the second conductive layer facing away from the first conductive layer;

[0111] - on the surface of the solid electrolyte layer and / or within the solid electrolyte layer;

[0112] - within the first conductive layer;

[0113] - within the second conductive layer.

[0114] In embodiment 7 of method 1 according to the present invention, method 1 is designed according to embodiment 1 or 2 thereof, wherein the capacitor is an aluminum capacitor, preferably a multilayer aluminum capacitor comprising one aluminum sheet or a plurality of stacked sheets.

[0115] In embodiment 8 of method 1 according to the invention, method 1 is designed according to embodiment 7 thereof, wherein in method step I) the aluminum foil is etched to give a porous electrode body.

[0116] In embodiment 9 of method 1 according to the present invention, method 1 is designed according to embodiment 7 or 8 thereof, wherein the method comprises at least one of the following method steps:

[0117] V) optionally applying a first conductive layer onto at least a portion of the solid electrolyte layer, wherein the first conductive layer is preferably a carbon layer;

[0118] VI) applying a second conductive layer to at least a portion of the solid electrolyte layer or to at least a portion of the first conductive layer, wherein the second conductive layer is a metal layer, preferably a silver layer;

[0119] VII) optionally applying an insulating layer to at least a portion of the surface of the electrode body or to a portion of the dielectric layer in such a way that electrically conductive contact between the electrode body and the solid electrolyte layer, the first conductive layer and the second conductive layer is avoided;

[0120] VIII) Optionally applying a covering layer to at least a portion of the region between the anode contact and the solid electrolyte layer.

[0121] In embodiment 10 of method 1 according to the present invention, method 1 is designed according to embodiment 9 thereof, wherein at least one metal ion migration inhibitor is applied at least at one, preferably a part of two or more of the following locations:

[0122] - on the surface of the anode contact;

[0123] - on the surface of the dielectric layer covering the electrode body;

[0124] - on the surface of the electrode body;

[0125] - on the surface of the covering layer;

[0126] - on the surface of the insulating layer or within the insulating layer;

[0127] - onto a surface of the first conductive layer facing the solid electrolyte layer or onto a surface of the first conductive layer facing away from the solid electrolyte layer;

[0128] on a surface of the second conductive layer facing the first conductive layer or on a surface of the second conductive layer facing away from the first conductive layer;

[0129] - on the surface of the solid electrolyte layer and / or within the solid electrolyte layer;

[0130] - within the first conductive layer;

[0131] - within the second conductive layer.

[0132] In embodiment 11 of method 1 according to the present invention, method 1 is configured according to any one of embodiments 1 to 10 thereof, wherein at least one metal ion migration inhibitor is applied to the surface of the solid electrolyte layer and / or introduced into the solid electrolyte layer.

[0133] In embodiment 12 of method 1 according to the present invention, method 1 is designed according to any one of its embodiments 1 to 11, wherein in method step II), a first solid electrolyte layer is deposited onto at least a portion of the surface of the dielectric layer, and then a second solid electrolyte layer is deposited onto at least a portion of the first solid electrolyte layer, wherein both the first solid electrolyte layer and the second solid electrolyte layer contain a conductive polymer as a solid electrolyte material.

[0134] In embodiment 13 of method 1 according to the present invention, method 1 is designed according to embodiment 12 thereof, wherein at least one of the following conditions is satisfied:

[0135] A) during or after method step II), at least one metal ion transport inhibitor is introduced into at least a portion of the first solid electrolyte layer;

[0136] B) during or after method step II), at least one metal ion transport inhibitor is introduced into at least a portion of the second solid electrolyte layer;

[0137] C) during or after method step II), at least one metal ion transport inhibitor is deposited onto at least a portion of the surface of the first solid electrolyte layer facing the second solid electrolyte layer;

[0138] D) During or after method step II), at least one metal ion transport inhibitor is deposited onto at least a portion of the surface of the second solid electrolyte layer facing away from the first solid electrolyte layer (103a).

[0139] In embodiment 14 of method 1 according to the present invention, method 1 is designed according to any one of its embodiments 11 to 13, wherein in method step II), depositing the solid electrolyte layer or the first solid electrolyte layer onto at least a part of the surface of the dielectric layer comprises the following steps:

[0140] - contacting the electrode body obtained in process step I) with a liquid composition comprising a conductive polymer and at least one solvent followed by at least partial removal of the solvent, or with a monomer for preparing a conductive polymer and an oxidizing agent followed by in situ polymerization of the monomer, or with a monomer for preparing a conductive polymer followed by electrochemical polymerization, so as to form a solid electrolyte layer or a first solid electrolyte layer;

[0141] and wherein the at least one metal ion transport inhibitor is introduced into the solid electrolyte layer or into the first solid electrolyte layer, or the at least one metal ion transport inhibitor is applied to the surface of these layers as follows:

[0142] a) by adding at least one metal ion migration inhibitor to a liquid composition comprising a conductive polymer or a monomer or an oxidizing agent for preparing a conductive polymer;

[0143] β) by contacting the solid electrolyte layer or the first solid electrolyte layer with a composition comprising at least one metal ion transport inhibitor; or

[0144] γ) by a combination of methods α) and β).

[0145] In embodiment 15 of method 1 according to the present invention, method 1 is designed according to any one of embodiments 12 to 14 thereof, wherein in method step II), depositing the second solid electrolyte layer onto at least a portion of the surface of the first solid electrolyte layer comprises the following steps:

[0146] - optionally contacting the electrode body on which the first solid electrolyte layer has been deposited with a primer solution comprising a primer compound and at least one solvent, followed by at least partial removal of the solvent, so as to form a primer layer;

[0147] - contacting the electrode body on which the first solid electrolyte layer has been deposited, or the electrode body on which the first solid electrolyte layer and the undercoat layer have been deposited, with a liquid composition comprising a conductive polymer and at least one solvent followed by at least partial removal of the solvent, or with a monomer for preparing a conductive polymer and an oxidizing agent followed by in situ polymerization of the monomer, or with a monomer for preparing a conductive polymer followed by electrochemical polymerization, so as to form a second solid electrolyte layer;

[0148] and wherein the at least one metal ion transport inhibitor is introduced into the second solid electrolyte layer, or the at least one metal ion transport inhibitor is applied to the surface of this layer as follows:

[0149] α) by adding at least one metal ion migration inhibitor to the primer solution;

[0150] β) by adding at least one metal ion migration inhibitor to a liquid composition comprising a conductive polymer or to a monomer or an oxidizing agent used to prepare a conductive polymer;

[0151] γ) by contacting the second solid electrolyte layer with a composition comprising at least one metal ion transport inhibitor; or

[0152] δ) by a combination of methods α), β) and / or γ).

[0153] In embodiment 16 of method 1 according to the present invention, method 1 is designed according to any one of embodiments 1 to 15 thereof, wherein the conductive polymer comprises polythiophene.

[0154] In Example 17 of Method 1 according to the present invention, Method 1 is designed according to its Example 16, wherein the polythiophene is an externally doped polythiophene, preferably a cationic polythiophene in the form of a polythiophene / polyanion complex; a self-doped polythiophene or a mixture thereof. Preferably, the conductive polymer comprises a composite of poly(3,4-ethylenedioxythiophene) and polystyrenesulfonic acid (PEDOT / PSS), poly(4-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]propane-1-sulfonic acid), poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)methoxy]butane-1-sulfonic acid) (PEDOT-S), poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)methoxy]butane-2-sulfonic acid) or a mixture thereof.

[0155] In embodiment 18 of method 1 according to the present invention, method 1 is designed according to any one of embodiments 1 to 17 thereof, wherein at least one metal ion migration inhibitor is selected from the group consisting of azoles or derivatives thereof, oxazines or derivatives thereof and amines.

[0156] In embodiment 19 of method 1 according to the present invention, method 1 is designed according to embodiment 18 thereof, wherein the azole is selected from the group consisting of: 4-methylimidazole, 4-methyl-5-imidazole-carboxaldehyde, ethyl-4-methyl-imidazole carboxylate, 4-methyl-1-(4-methoxyphenyl)imidazole, benzimidazole, (mercaptobenzimidazole)pyrazole, 2-undecylimidazole, poly-N-vinylimidazole, 1,2,3-triazole, 1,2,4-triazole, 5-methyl-1H-benzotriazole, tetrazole, pentazole, oxazole, isoxazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, oxadiazole, thiazole, isothiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 2-amino-5-ethylthio-1,3,4-thiadiazole, 2-amino-5-ethyl-1,3,4-thiadiazole, 3-amino-5-methyl-thio-1,2,4-triazole, 1-(p-tolyl)-4-methylimidazole, 1-phenyl-4-methylimidazole, 4-methyl-5-hydroxymethylimidazole, (2-mercapto-1-methylimidazole), 5-mercapto-1-phenyl-1H-tetrazole, 2-(3,5-di-tert-butyl-2-hydroxyphenyl)benzotriazole and derivatives of these azoles.

[0157] In embodiment 20 of method 1 according to the present invention, method 1 is designed according to embodiment 19 thereof, wherein the azole is selected from the group consisting of 1,2,4-triazole, 5-methyl-1H-benzotriazole and derivatives or mixtures thereof.

[0158] In embodiment 21 of method 1 according to the present invention, method 1 is designed according to embodiment 20 thereof, wherein the azole is 5-methyl-1H-benzotriazole or a derivative thereof.

[0159] In Example 22 of method 1 according to the present invention, method 1 is designed according to its Example 18, wherein the azole is selected from the group consisting of: bismuth reagent (1,5-dimercapto-1,3,4-thiadiazole), benzoxazole, 2-ethyl-4-methylimidazole, 1-allylimidazole, 4-methyl-2-phenylimidazole, 1-propylimidazole and derivatives of these azoles, preferably selected from the group consisting of: bismuth reagent, benzoxazole and 4-methyl-2-phenylimidazole.

[0160] In embodiment 23 of method 1 according to the present invention, method 1 is designed according to embodiment 18 thereof, wherein the oxazine is selected from the group consisting of aromatic hydrazines, oxines, pyridines, pyridazines, pyrimidines, pyrazines, triazinones, tetrazines and derivatives of these oxazines.

[0161] In embodiment 24 of method 1 according to the present invention, method 1 is designed according to its embodiment 23, wherein the azine is selected from the group consisting of: pyrazine-2,3-dicarboxamide, pyridine-2-amine, 3-amino-pyrazine 2-carboxylic acid, pyridine-2,3-diamine, pyrazine-2-amine, 2-(3-phenyl-4,5-dihydro-1H-pyrazol-5-yl)pyridine, 2-(3-phenyl-4,5-dihydro-1,2-oxazol-5-yl)-pyridine and 1,2-bis(4-chloro-benzylidene)oxazine.

[0162] In embodiment 25 of method 1 according to the present invention, method 1 is designed according to its embodiment 18, wherein the oxazine is selected from the group consisting of: 2-methyl-8-hydroxyquinoline, allopurinol (1H-pyrazolo[3,4-d]pyrimidin-4-one), 2-amino-5-methylpyridine, benzoguanamine, 2,3-dimethylpyrazine, thiocyanic acid and derivatives of these oxazines, preferably selected from the group consisting of: allopurinol, benzoguanamine, 2,3-dimethylpyrazine and thiocyanic acid.

[0163] In Example 26 of Method 1 according to the present invention, Method 1 is designed according to Example 18 thereof, wherein the amine is selected from the group consisting of ethanolamine, ethylamine, butylamine, isopropylamine, triethanolamine, aniline, benzylamine, octylamine, 2-ethylhexylamine, (N-(2-furylmethyl)-p-toluidine), (N-(5-chloro-2-furylmethyl)-p-toluidine), (N-(5-bromo-2-furylmethyl)-p-toluidine), (N-(5-nitro-2-furylmethyl)-p-toluidine), (N-(5-methyl-2-furylmethyl)-p-toluidine), N-methyl-p-toluidine, 2-(3-methoxyphenyl)ethylamine and 2-ethylhexylamine.

[0164] In embodiment 27 of method 1 according to the invention, method 1 is designed according to any of its embodiments 1 to 26, wherein at least one metal ion migration inhibitor is introduced into the capacitor in an amount of 1 ppm to 10%, preferably 5 ppm to 1%, more preferably 10 ppm to 0.1%, in each case based on the total weight of the capacitor. The at least one metal ion migration inhibitor is preferably introduced into the solid electrolyte layer, preferably at least into the second solid electrolyte layer, in each case based on the weight of the solid electrolyte layer, preferably based on the weight of the second solid electrolyte layer, in an amount in the range of 0.05% to 90%, more preferably 1% to 75%, even more preferably in the range of 5% to 50%.

[0165] In embodiment 28 of method 1 according to the present invention, method 1 is designed according to any one of embodiments 1 to 27 thereof, wherein the metallized copper is selected from the group consisting of:

[0166] -Cu / Ni[Cu plated with Ni]

[0167] -Cu / Ni / Pd[Cu / Ni plated with Pd]

[0168] -Cu / Ni / Pd / Au[Au-plated Cu / Ni / Pd]

[0169] -Cu / Ni / Au[Au-plated Cu / Ni]

[0170] -Cu / Au[Au-plated Cu]

[0171] -Cu / Pd[Cu plated with Pd]

[0172] -Cu / Ni / Sn[Cu / Ni plated with Sn]

[0173] -Cu / Ni-Sn[Cu plated with Ni-Sn alloy]

[0174] -Cu / Sn[Cu plated with Sn]

[0175] -Cu / (Ni / )Cu-Sn [Cu-plated Cu-Sn alloy].

[0176] In embodiment 29 of method 1 according to the present invention, method 1 is designed according to any one of embodiments 1 to 28 thereof, wherein the copper alloy is selected from the group consisting of Cu—Sn—P, Cu—Ni—Sn and Cu—Sn—Ni—Zn.

[0177] Embodiment 1 of a capacitor 2 obtainable by a method according to the invention according to any of its embodiments 1 to 29 contributes to solving at least one of the objects according to the invention. In a preferred embodiment of the capacitor 2, this capacitor 2 exhibits the technical features of the capacitor 1 according to the invention according to any of its embodiments.

[0178] Embodiment 1 of the electronic circuit comprising a capacitor 1 according to any of the preferred embodiments or a capacitor 2 according to any of its preferred embodiments also contributes to solving at least one of the objects according to the invention.

[0179] The capacitor 1 according to any of its preferred embodiments or the capacitor 2 according to any of its preferred embodiments in an electronic circuit also contributes to solving at least one of the objects according to the invention.

[0180] Electrode body

[0181] In principle, the electrode body can be produced by pressing a valve metal powder with a high surface area and sintering it to obtain a generally porous electrode body. Electrical contact wires or strips of a preferred valve metal, such as tantalum, are conventionally also pressed into the electrode body here or welded to the electrode body after sintering. The electrode body is then coated with a dielectric layer, i.e. an oxide layer, for example by electrochemical oxidation. Alternatively, the metal foil can also be etched and coated with a dielectric layer by electrochemical oxidation in order to obtain an anode foil with a porous area. In a wound capacitor, the anode foil with a porous area forming the electrode body is separated from the cathode foil by a separator and wound upward.

[0182] In the context of the present invention, valve metals are understood to mean those metals whose oxide layers do not allow possible current to flow equally in both directions. In the case of an anode voltage, the oxide layer of the valve metal blocks the current, and in the case of a cathode voltage, a large current occurs, 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, and alloys or compounds of at least one of these metals with other elements. The most famous representatives of valve metals are Al, Ta and Nb. Compounds with electrical properties comparable to valve metals are those compounds with metallic conductivity, which can be oxidized and whose oxide layers have the above-mentioned properties. For example, NbO has metallic conductivity, but is generally not considered a valve metal. However, the oxidized NbO layer has the typical properties of a valve metal oxide layer, so NbO or alloys or compounds of NbO with other elements are typical examples of such compounds with electrical properties comparable to valve metals. Electrode bodies comprising tantalum, aluminum and those electrode materials based on niobium or niobium oxide are preferred. Tantalum and aluminum are particularly preferred as electrode materials (and the corresponding oxides as dielectric materials).

[0183] For simplicity, a body with a porous area is also referred to as porous in the following text. Thus, for example, an electrode body with a porous area is also referred to as a porous electrode body. On the one hand, a porous body can be permeable by a plurality of channels and is therefore sponge-like. This is often the case when tantalum is used to construct a capacitor. Furthermore, it is possible that only the surface has pores in the construction and the area below the surface pores is solid. This is often observed when aluminum is used to construct a capacitor. Preferably, the electrode body is porous.

[0184] The usually porous electrode body produced in this way is then oxidized, for example in a suitable electrolyte, such as aqueous phosphoric acid or ammonium adipate solution, by applying a voltage to form a dielectric layer. The level of this forming voltage depends on the oxide layer thickness to be achieved or the capacitor voltage subsequently used. Preferably, the forming voltage is in the range of 1 V to 500 V, particularly preferably in the range of 2 V to 150 V, and very preferably in the range of 3 V to 100 V.

[0185] The usual porous electrode body preferably used has a porosity of 10 to 90%, preferably 30 to 80%, particularly preferably 50 to 80%, and an average pore diameter of 10 nm to 10,000 nm, preferably 20 nm to 5,000 nm, particularly preferably 50 nm to 3,000 nm.

[0186] Solid electrolyte layer

[0187] The solid electrolyte layer in the capacitor according to the present invention comprises a polymer, wherein the conductive polymer preferably comprises polythiophene. Preferably, the polythiophene is a polythiophene having repeating units of the general formula (I), the general formula (II), the general formula (III) or a polythiophene comprising a combination of these repeating units:

[0188]

[0189] in

[0190] A is an optionally substituted C1-C5 alkylene group,

[0191] R is independently H, a linear or branched optionally substituted C1-C 18 Alkyl, optionally substituted C5-C 12 Cycloalkyl, optionally substituted C6-C 14 Aryl, optionally substituted C7-C 18 aralkyl, optionally substituted C1-C4 hydroxyalkyl or hydroxy,

[0192] x is an integer from 0 to 8, and

[0193] Where multiple R groups are bonded to A, they may be the same or different.

[0194] The general formulae (I) and (II) are to be understood such that x substituents R can be bonded to the alkylene radical A.

[0195] Particularly preferred are polythiophenes having repeating units of the formula (I) or (II) or repeating units of the formulae (I) and (II), wherein A is an optionally substituted C2-C3 alkylene group and x is 0 or 1. Very preferred polythiophenes are poly(3,4-ethylenedioxythiophene) (PEDOT), which is optionally substituted, such as in poly(4-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]propane-1-sulfonic acid), poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)methoxy]butane-1-sulfonic acid) (PEDOT-S) or poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)methoxy]butane-2-sulfonic acid).

[0196] In the context of the present invention, the prefix "poly" is understood to mean that more than one identical or different repeating unit is present in the polymer or polythiophene. The polythiophene contains a total of n repeating units of the general formula (I) or the general formula (II) or the general formula (III), or repeating units of the general formula (I) and (II), or repeating units of the general formula (I) and (III), or repeating units of the general formula (II) and (III), or repeating units of the general formula (I), (II) and (III), wherein n is an integer from 2 to 2000, preferably from 2 to 100. The repeating units of the general formula (I) or the general formula (II) or the general formula (III), or repeating units of the general formula (I) and (II), or repeating units of the general formula (I) and (III), or repeating units of the general formula (II) and (III), or repeating units of the general formula (I), (II) and (III), may each be identical or different in the polythiophene. Preference is given to polythiophenes which have in each case the same repeating units of the general formula (I) or of the general formula (II) or of the general formula (III), or in each case the same repeating units of the general formulae (I) and (II), or of the general formulae (I) and (III), or of the general formulae (II) and (III), or in each case the same repeating units of the general formulae (I), (II) and (III). Particular preference is given to polythiophenes which have in each case the same repeating units of the general formulae (I) or (II), or in each case the same repeating units of the general formulae (I) and (II). The polythiophenes preferably each carry H at the end groups.

[0197] In the context of the present invention, C1-C5 alkylene A is preferably methylene, ethylene, n-propylene, n-butylene or n-pentylene. 18 The alkyl group R is preferably a linear or branched C1-C 18 Alkyl, 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 Aryl R is, for example, phenyl or naphthyl, and C7-C 18 Aralkyl 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 mesityl. The above list serves to illustrate the invention by way of example and should not be considered exclusive.

[0198] In the context of the present invention, any other substituents of the A group and / or the R group include many organic groups, such as alkyl, cycloalkyl, aryl, aralkyl, alkoxy, halogen, ether, thioether, disulfide, sulfoxide, sulfone, sulfonate, amino, aldehyde, ketone, carboxylic ester, carboxylic acid, carbonate, carboxylate, cyano, alkylsilane and alkoxysilane groups and carboxamide.

[0199] Polythiophene can be uncharged or cationic. In a preferred embodiment, it is cationic, and "cationic" only relates to the charge retained on the polythiophene main chain. Depending on the substituents on the R groups, polythiophene can carry positive and negative charges in the structural unit, in which case the positive charge is located on the polythiophene main chain and the negative charge (if present) is located on the R group substituted with sulfonate or carboxylate groups. The positive charge of the polythiophene main chain can be partially or completely saturated by anionic groups that may be present on the R groups. Overall, in these cases, polythiophene can be cationic, uncharged or even anionic. However, in the context of the present invention, all are considered to be cationic polythiophenes because the positive charge on the polythiophene main chain is very critical. The positive charge is not shown in the formula because its exact number and position cannot be clearly indicated. However, the number of positive charges is at least 1 and at most n, where n is the total number of all repeating units (same or different) in the polythiophene.

[0200] The positive charge of the polythiophene can be balanced by R groups which are substituted with sulfonates or carboxylates and are therefore negatively charged (so-called “self-doped polythiophenes”) or by counterions (so-called “exo-doped polythiophenes”).

[0201] According to a first preferred embodiment of the polythiophene which can be used to form the solid electrolyte layer, the polythiophene is a self-doped polythiophene which preferably comprises recurring units of formula (I) to an extent of at least 50%, more preferably to an extent of at least 75%, more preferably to an extent of at least 95% and most preferably to an extent of 100%

[0202]

[0203] in

[0204] X, Y are the same or different and represent O, S, NR 1 ,

[0205] Z represents -(CH2) m -CR 2 R 3 -(CH2) n -,

[0206] R 1 Represents aromatic group, C1-C 18Alkyl or hydrogen,

[0207] R 2 Represents hydrogen, -(CH2) s -O-(CR 4 2) p -SO3 - M + or -(CH2) p -SO3 - M + ,

[0208] R 3 Represents -(CH2) s -O-(CR 4 2) p -SO3 - M + or -(CH2) p -SO3 - M + ,

[0209] M + represents a cation,

[0210] m and n are the same or different and represent an integer from 0 to 3,

[0211] R 4 Represents hydrogen or C1-C 10 Alkyl, preferably methyl,

[0212] s represents an integer from 0 to 10, and

[0213] p represents an integer from 1 to 18.

[0214] The abovementioned percentage figures are in this case intended to indicate the number of units of the formula (I) out of the total number of monomer units of the self-doped conductive polymer.

[0215] Suitable cation M + For example, H + , Li + 、Na + , K + , Rb + , Cs + and NH4 + A particularly suitable cation is Na + and K + .

[0216] Particularly preferred monomers of formula (I) are those wherein

[0217] X, Y represents O,

[0218] Z represents -(CH2) m-CR 2 R 3 -(CH2) n -,

[0219] R 2 Represents hydrogen or -(CH2) s -O-(CH2) p -SO3 - M + 、-(CH2) p -SO3 - M + or -(CH2) s -O-(CH2) p -CHR 4 -SO3 - M + ,

[0220] R 3 Represents -(CH2) s -O-(CH2) p -SO3 - M + 、-(CH2) p -SO3 - M + or -(CH2) s -O-(CH2) p -CHR 4 -SO3 - M + ,

[0221] M + represents a cation,

[0222] m and n are the same or different and represent an integer from 0 to 3,

[0223] R 4 represents hydrogen, methyl or ethyl;

[0224] s represents an integer from 0 to 10, and

[0225] p represents an integer from 1 to 18.

[0226] Very preferred monomers of formula (I) are those wherein

[0227] X, Y represents O,

[0228] Z represents -(CH2)-CR 2 R 3 -(CH2) n -,

[0229] R 2 represents hydrogen,

[0230] R 3 Represents -(CH2) s -O-(CH2) p -SO3 - M + 、-(CH2) p -SO3 - M + or -(CH2) s -O-(CH2) p -CH(CH3)-SO3 - M + or -(CH2) s -O-(CH2) p -CH(CH2CH3)-SO3 - M + ,

[0231] M + Indicates Na + or K+,

[0232] n represents 0 or 1,

[0233] s represents 0 or 1, and

[0234] p means 2, 3, 4, or 5.

[0235] Suitable examples of self-doping polymers are disclosed in WO-A-2014 / 048562 and in US-A-2015 / 0337061. Specific examples of very preferred self-doping conductive polymers include poly(4-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]propane-1-sulfonic acid), poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)methoxy]butane-1-sulfonic acid) (PEDOT-S), poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)methoxy]butane-2-sulfonic acid) or mixtures thereof.

[0236] According to a second preferred embodiment of the polythiophene that can be used to form the solid electrolyte layer, the polythiophene is an exo-doped polythiophene, which preferably contains monomeric or polymeric counterions to balance the positive charge, the latter also referred to as polyanions hereinafter. Thus, according to a preferred embodiment of the capacitor according to the invention, the conductive polymer in the solid electrolyte layer is a cationic polymer, which contains polymeric anions that act as counterions for the polythiophene.

[0237] Polymeric anions are preferred over monomeric anions because they promote film formation and, due to their size, produce more thermally stable conductive films. In this context, polymeric anions may 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 polyvinyl sulfonic acid. These polycarboxylic acids and polysulfonic acids may also be copolymers of vinyl carboxylic acids and vinyl sulfonic acids with other polymerizable monomers, such as acrylates and styrene.

[0238] Preferred polyanions in the conjugated polymer b) are anions of polymeric carboxylic or sulfonic acids. Particularly preferred polyanions are anions of polystyrenesulfonic acid (PSS) or its derivatives.

[0239] The molecular weight of the polyacid providing the polyanion is preferably from 1000 to 2000000, more preferably from 2000 to 500000. The polyacids or their alkali metal salts are commercially available, for example polystyrene sulfonic acid and polyacrylic acid, or can be prepared by known methods (see, for example, Houben Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Vol. E 20 Makromolekulare Stoffe [Macromolecular Substances], Part 2, (1987), p. 1141 et seq.).

[0240] The polyanion(s) and the conductive polymer may be present in the dispersion a) in a weight ratio of 0.5:1 to 50:1, preferably 1:1 to 30:1, more preferably 2:1 to 20: 1. The weight of the conductive polymer in this context corresponds to the initial weight of the monomers used, assuming complete conversion in the polymerization.

[0241] The monomer anions used are, for example, C1-C 20 Anions of alkanesulfonic acids, such as methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, butanesulfonic acid or higher carbon number sulfonic acids, such as dodecanesulfonic acid; anions of aliphatic perfluorosulfonic acids, such as trifluoromethanesulfonic acid, perfluorobutanesulfonic acid or perfluorooctanesulfonic acid; anions of aliphatic C1-C 20 anions of carboxylic acids, such as 2-ethylhexyl carboxylic acid; anions of aliphatic perfluorocarboxylic acids, such as trifluoroacetic acid or perfluorooctanoic acid; and optionally C1-C 20Alkyl substituted aromatic sulfonic acids, such as anions of benzenesulfonic acid, o-toluenesulfonic acid, p-toluenesulfonic acid or dodecylbenzenesulfonic acid; and cycloalkanesulfonic acids, such as anions of camphorsulfonic acid; or tetrafluoroborate, hexafluorophosphate, perchlorate, hexafluoroantimonate, hexafluoroarsenate or hexachloroantimonate. Preferred monomeric anions are anions of p-toluenesulfonic acid, methanesulfonic acid or camphorsulfonic acid.

[0242] A specific example of a highly preferred out-doped conductive polymer is a composite of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonic acid (PEDOT / PSS).

[0243] To form the solid electrolyte layer, a solution or dispersion containing a conductive polymer, such as a PEDOT / PSS dispersion or a PEDOT-S solution, can be introduced into the electrode body, followed by at least partial removal of the solvent or dispersant to form the solid electrolyte layer. This step can be repeated several times until a solid electrolyte layer of the desired thickness is obtained. Furthermore, it is also possible to form the solid electrolyte layer in the electrode body by polymerizing monomers for preparing the conductive polymer, such as 3,4-ethylenedioxythiophene, in a so-called in situ polymerization process. It may also be advantageous to use a combination of externally doped polythiophenes, such as PEDOT / PSS, and self-doped polythiophenes, such as PEDOT-S, to form the solid electrolyte layer, as disclosed, for example, in WO-A-2014 / 048562.

[0244] According to a particularly preferred embodiment of the capacitor according to the invention, the solid electrolyte layer comprises a first solid electrolyte layer after the dielectric layer and a second solid electrolyte layer after the first solid electrolyte layer, wherein the first solid electrolyte layer and the second solid electrolyte layer both comprise a conductive polymer as solid electrolyte material. The second solid electrolyte layer serves as a polymeric outer layer, as disclosed, for example, in US-A-2007 / 171597. Preferably, the solid electrolyte layers both comprise self-doped polythiophene or externally doped polythiophene, such as PEDOT, PEDOT / PSS, PEDOT-S or a mixture thereof as a conductive polymer.

[0245] In this case, it is also preferred to cover the first solid electrolyte layer with a primer compound before applying the second solid electrolyte layer to improve the coverage of the first solid electrolyte layer by the polymerized outer layer. Suitable primers and methods for applying such primers are disclosed, for example, in WO-A-2010 / 089111, pages 7-14 (where the primer compound is referred to as "crosslinking agent e)"), WO-A-2015 / 181347, pages 12-15 (where the primer compound is referred to as "primer compound e)") or WO-A2015 / 181348, pages 11-14 (where the primer compound is referred to as a combination of "monofunctional amine and at least one carboxylic acid").

[0246] Metal Ion Migration Inhibitors

[0247] The capacitor according to the invention is characterized in that it contains at least one metal ion migration inhibitor. In the sense of the present invention, a "metal ion migration inhibitor" is preferably a metal ion migration inhibitor that is able to react with copper ions (Cu 2+ Cu + ) any compound that forms a chelate complex, preferably a water-insoluble chelate complex.

[0248] According to a preferred embodiment of the capacitor according to the invention, at least one metal ion migration inhibitor is selected from the group consisting of: azoles or derivatives thereof and oxazines or derivatives thereof. In the sense of the present invention, "azoles" are preferably any compounds comprising a five-membered aromatic heterocyclic ring system containing a nitrogen atom and at least one other non-carbon atom (i.e. nitrogen, sulfur or oxygen) as part of the ring system. Derivatives of azoles are preferably compounds wherein one or more hydrogen atoms are replaced by a C1-C 20 In the sense of the present invention, "azine" is any condensation product obtainable when reacting hydrazine with ketone or aldehyde, or any aromatic compound containing a 6-membered aromatic heterocyclic ring system containing at least one nitrogen. Derivatives of aromatic azines are preferably those in which one or more hydrogen atoms are replaced by a C1-C 20 Any compound substituted with a residue of an alkyl group, a hydroxyl group, a halogen atom, an amino group or a carboxyl group. According to a particularly preferred embodiment of the capacitor according to the invention, at least one metal ion migration inhibitor is 5-methyl-1H-benzotriazole.

[0249] Suitable migration inhibitors are

[0250] -azoles, such as 4-methylimidazole, 4-methyl-5-imidazole-carboxaldehyde, ethyl-4-methyl-imidazole carboxylate, 4-methyl-1 (4-methoxy-phenyl) imidazole, benzimidazole, (mercaptobenzimidazole) pyrazole, 2-undecylimidazole, poly-N-vinylimidazole, 1,2,3-triazole, 1,2,4-triazole, 5-methyl-1H-benzotriazole, tetrazole, pentazole, oxazole, isoxazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, thiazole, isothiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 2-amino- 5-ethylthio-1,3,4-thiadiazole, 2-amino-5-ethyl-1,3,4-thiadiazole, 3-amino-5-methyl-thio-1,2,4-triazole, 1-(p-tolyl)-4-methylimidazole, 1-phenyl-4-methylimidazole, 4-methyl-5-hydroxymethylimidazole, (2-mercapto-1-methylimidazole), 5-mercapto-1-phenyl-1H-tetrazole, 2-(3,5-di-tert-butyl-2-hydroxyphenyl)benzotriazole, bismuth reagent (1,5-dimercapto-1,3,4-thiadiazole), benzoxazole, 2-ethyl-4-methylimidazole, 1-allylimidazole, 4-methyl-2-phenylimidazole, 1-propylimidazole or derivatives of these azoles,

[0251] -oxazines, such as aromatic hydrazines, oxines, pyridines, pyridazines, pyrimidines, pyrazines, triazinones, tetrazines and derivatives of these azines, for example pyrazine-2,3-dicarboxamide, pyridine-2-amine, 3-amino-pyrazine-2-carboxylic acid, pyridine-2,3-diamine, pyrazin-2-amine, 2-(3-phenyl-4,5-dihydro-1H-pyrazol-5-yl)pyridine, 2-(3-phenyl-4,5-dihydro-1,2-oxazol-5-yl)-pyridine, 1,2-bis(4-chloro-benzylidene)oxazine, 2-methyl-8-hydroxyquinoline, allopurinol (1H-pyrazolo[3,4-d]pyrimidin-4-one), 2-amino-5-methylpyridine, benzoguanamine, 2,3-dimethylpyrazine, thiocyanic acid or derivatives of these azines,

[0252] -amines, such as ethanolamine, ethylamine, butylamine, isopropylamine, triethanolamine, aniline, benzylamine, octylamine, 2-ethylhexylamine, (N-(2-furylmethyl)-p-toluidine), (N-(5-chloro-2-furylmethyl)-p-toluidine), (N-(5-bromo-2-furylmethyl)-p-toluidine), (N-(5-nitro-2-furylmethyl)-p-toluidine), (N-(5-methyl-2-furylmethyl)-p-toluidine), N-methyl-p-toluidine, 2-(3-methoxyphenyl)ethylamine or 2-ethylhexylamine.

[0253] Particularly preferred metal ion migration inhibitors are 1,2,4-triazole and 5-methyl-1H-benzotriazole or derivatives thereof, with 5-methyl-1H-benzotriazole being most preferred.

[0254] The metal migration inhibitor is preferably applied in the form of a liquid composition comprising the metal ion migration inhibitor, optionally a solvent or dispersant (especially if the inhibitor itself is not liquid at room temperature), and optionally one or more additives selected from the group consisting of surfactants, binders, crosslinkers, viscosity modifiers and pH modifiers.

[0255] Test Method

[0256] To determine copper migration, the Figure 7 and 8 The experimental configuration shown in .

[0257] Experimental Configuration I Figure 7 ):

[0258] A glass plate of size 25 mm × 100 mm is used as a substrate. A polyimide film containing an arrow-shaped opening is deposited onto a substrate 112. Some drops of a solid electrolyte dispersion are introduced into the opening. The polyimide mask is removed after the dispersion is dried, leaving an arrow-shaped conductive polymer layer 113 (simulating a solid electrolyte layer) on the substrate. An arrow-shaped copper tape 114 is glued to the substrate 112. The tip of the copper tape 114 and the tip of the conductive polymer layer 113 face each other. The distance between the two tips is set to 1 mm. A PTFE frame 115 is glued to the substrate 112, and the two tips are positioned at the center of the frame. The frame 115 is filled with 50 to 100 μl of deionized water 116 (moisture that may accumulate during the operation of the capacitor in a humid atmosphere). A voltage of 20 VDC is applied between the conductive polymer layer and the copper tape, and the copper tape 114 is set as an anode and the arrow-shaped conductive polymer layer 113 is set as a cathode. The current is monitored over time after the voltage is applied.

[0259] Experimental Configuration II Figure 8 ):

[0260] Experimental configuration II follows experimental configuration I, with the difference that the conductive polymer layer is replaced by a tantalum capacitor. One edge of the tantalum capacitor 117 is positioned adjacent to the tip of the copper tape 114, at a distance of 1 mm. A PTFE frame 115 is glued to the substrate 112, with the tips of the tantalum capacitor 117 and the copper tape 114 positioned at the center of the frame. The frame is filled with deionized water 116. A voltage of 20 VDC is applied between the solid electrolyte layer of the tantalum capacitor 117 and the copper tape 114, with the copper tape set as the anode and the solid electrolyte layer set as the cathode. The current is monitored over time after the voltage is applied.

[0261] The following figures and examples are intended to illustrate the present invention by way of example and are not to be construed as limiting.

[0262] Examples

[0263] Preparation Example 1 (Synthesis of Conductive Polymers):

[0264] First, 1736g of deionized water and 660g of polystyrene sulfonic acid aqueous solution with 70000g / mol mean molecular weight and 3.8wt.% solid content are introduced into a 5l glass reactor with agitator and a thermometer. The reaction temperature is maintained between 20°C and 25°C. While stirring, 10.2g of 3,4-ethylenedioxythiophene is added. The solution is stirred for 30 minutes. Subsequently, 0.06g of iron sulfate (III) and 19g of sodium persulfate are added and the solution is stirred for 24 hours. After the reaction has finished, 200ml of strongly acidic cation exchanger and 500ml of weakly basic anion exchanger are added and the solution is stirred for 2 hours to remove inorganic salts. The ion exchanger is filtered out.

[0265] Preparation Example 2 (Preparation of conductive polymer for first solid electrolyte layer):

[0266] A portion of the poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate dispersion from Preparation Example 1 was homogenized ten times using a high-pressure homogenizer at a pressure of 1500 bar.

[0267] 90 g of this PEDOT / PSS dispersion was stirred with 10 g of dimethyl sulfoxide.

[0268] Preparation Example 3 (Preparation of conductive polymer for second solid electrolyte layer):

[0269] 160 g of the dispersion from Preparation Example 1, 28 g of water, 6 g of sulfo-polyester and 8 g of dimethyl sulfoxide were mixed vigorously in a glass beaker with a stirrer for one hour.

[0270] Preparation Example 4 (Preparation of primer solution):

[0271] 4.0 g of p-toluenesulfonic acid monohydrate, 1.7 g of 1,10-diaminodecane and 95.5 g of water were vigorously mixed in a glass beaker with a stirrer.

[0272] Preparation Example 5 (For the production of electrode bodies for tantalum electrolytic capacitors):

[0273] Tantalum powder with a specific capacitance of 70000 CV / g was pressed into agglomerates containing tantalum wires and sintered to form porous electrode bodies with dimensions of 1.5 mm×2.9 mm×4.0 mm. Five of these porous electrode bodies were anodized at 30 V in a phosphoric acid electrolyte to form a dielectric to obtain capacitor bodies.

[0274] Preparation Example 6 (Capacitor production):

[0275] The capacitor body from Preparation Example 5 was immersed in the composition from Preparation Example 2 for 1 minute. Thereafter, it was dried at 120° C. for 10 minutes. The immersion and drying were repeated nine times. The capacitor body was then immersed in the dispersion from Preparation Example 3. Thereafter, it was dried at 120° C. for 10 minutes.

[0276] The capacitor body was subsequently immersed in the solution from Preparation Example 4. Thereafter, it was dried at 120° C. for 10 minutes. The capacitor body was subsequently immersed in the dispersion from Preparation Example 3. Thereafter, it was dried at 120° C. for 10 minutes.

[0277] Preparation Example 7 (Capacitor production):

[0278] The capacitor body from Preparation Example 5 was immersed in a solution consisting of one part by weight of 3,4-ethylenedioxythiophene and 20 parts by weight of a 40 wt. % ethanol solution of iron (III) p-toluenesulfonate.

[0279] The impregnated capacitor body is then dried at room temperature (20° C.) for 30 minutes. Thereafter, it is heat treated in a drying oven at 50° C. for 30 minutes. The capacitor body is then washed in an aqueous solution of 2 wt.% p-toluenesulfonic acid for 60 minutes. The capacitor body is reshaped in an aqueous solution of 0.25 wt.% p-toluenesulfonic acid for 30 minutes and then rinsed in distilled water and dried. The described impregnation, drying, heat treatment and reshaping are carried out twice more with the same capacitor body.

[0280] The capacitor body was subsequently immersed in the dispersion from Preparation Example 3. Thereafter, it was dried at 120° C. for 10 minutes.

[0281] The capacitor body was subsequently immersed in the solution from Preparation Example 4. Thereafter, it was dried at 120° C. for 10 minutes. The capacitor body was subsequently immersed in the dispersion from Preparation Example 3. Thereafter, it was dried at 120° C. for 10 minutes.

[0282] Preparation Example 8 (Capacitor production):

[0283] The capacitor body from Preparation Example 5 was immersed in a solution consisting of one part by weight of 3,4-ethylenedioxythiophene and 20 parts by weight of a 40 wt. % ethanol solution of iron (III) p-toluenesulfonate.

[0284] The impregnated capacitor body was then dried at room temperature (20° C.) for 30 minutes. Thereafter, it was heat treated in a drying oven at 50° C. for 30 minutes. The capacitor body was then washed in an aqueous solution of 2 wt.% p-toluenesulfonic acid for 60 minutes. The capacitor body was reshaped in an aqueous solution of 0.25 wt.% p-toluenesulfonic acid for 30 minutes and then rinsed in distilled water and dried. The described impregnation, drying, heat treatment and reshaping were repeated five more times with the same capacitor body.

[0285] Preparation Example 9 (Capacitor production):

[0286] The capacitor body from Preparation Example 5 was immersed in a solution consisting of one part by weight of 3,4-ethylenedioxythiophene and 20 parts by weight of a 40 wt. % ethanol solution of iron (III) p-toluenesulfonate.

[0287] The impregnated capacitor body was then dried at room temperature (20° C.) for 30 minutes. Thereafter, it was heat treated in a drying oven at 50° C. for 30 minutes. The capacitor body was then washed in an aqueous solution of 2 wt.% p-toluenesulfonic acid for 60 minutes. The capacitor body was reshaped in an aqueous solution of 0.25 wt.% p-toluenesulfonic acid for 30 minutes, and then rinsed and dried in distilled water. The described impregnation, drying, heat treatment and reshaping were performed twice more in the case of the same capacitor body. The capacitor body was then placed in an electrochemical cell containing a 0.05 mole solution of 3,4-ethylenedioxythiophene and 0.1 mole of tetrabutylammonium tetrafluoroborate in acetonitrile. A positive current of 2 mA was applied to the outside of the capacitor body for 2000 seconds. Thus, the capacitor body was plated with a layer of poly(3,4-ethylenedioxythiophene). The capacitor body was then washed and dried in acetonitrile.

[0288] Example 1:

[0289] The dispersion of Preparation Example 3 was mixed with the following metal ion migration inhibitor, applied to Experimental Configuration I and dried at 120°C for 10 minutes.

[0290] Table 1

[0291] Examples Metal Ion Migration Inhibitors quantity 1a none 1b 1,2,4-Triazole 1wt.% 1c 1,2,4-Triazole 5wt.% 1d 5-Methyl-1H-benzotriazole 0.3wt.%

[0292] Copper migration was determined by experimental configuration I described above:

[0293] Table 2

[0294] Examples Current after 1 minute Current after 3 minutes 1a 0.066mA 0.276mA 1b 0.028mA 0.160mA 1c 0.020mA 0.019mA 1d 0.013mA 0.013mA

[0295] Copper dendrite growth was observed from the conductive polymer layer toward the copper strip. The absolute current level and the increase in current level over time correlated with the amount of copper dendrites and the rate of dendrite formation. The metal ion migration inhibitor in the conductive polymer layer in Examples 1b, 1c, and 1d significantly reduced copper dendrite formation compared to Example 1a without the metal migration inhibitor.

[0296] Comparative Example 1:

[0297] A capacitor was prepared according to Preparation Example 6.

[0298] From the capacitor bodies thus obtained, copper migration was determined by means of the experimental configuration II described above. The time at which the current was increased to 2 mA was measured. The results are shown in Table 3.

[0299] Example 2:

[0300] Capacitors were prepared according to Preparation Example 6, except that 0.3 wt.% 5-methyl-1H-benzotriazole was introduced as a metal inhibitor into the conductive polymer dispersion of Preparation Example 3. Copper migration was determined from the capacitor bodies thus obtained by the experimental configuration II described above. The time at which the current was increased to 2 mA was measured. The results are shown in Table 3.

[0301] Example 3:

[0302] Capacitors were prepared according to Preparation Example 6, except that 3 wt.% 5-methyl-1H-benzotriazole was introduced as a metal inhibitor into the conductive polymer dispersion of Preparation Example 4. Copper migration was determined from the capacitor bodies thus obtained by the experimental configuration II described above. The time at which the current was increased to 2 mA was measured. The results are shown in Table 3.

[0303] Example 4:

[0304] Capacitors were prepared according to Preparation Example 6. After preparation, the capacitor bodies were immersed in an aqueous solution of 0.3 wt.% 5-methyl-1H-benzotriazole for 1 minute and then dried at 120°C for 10 minutes. Copper migration was determined from the capacitor bodies thus obtained by the experimental configuration II described above. The time at which the current was increased to 2 mA was measured. The results are shown in Table 3.

[0305] Example 5:

[0306] Capacitors were prepared according to Preparation Example 7. After preparation, the capacitor bodies were immersed in an aqueous solution of 0.3 wt.% 5-methyl-1H-benzotriazole for 1 minute and then dried at 120°C for 10 minutes. Copper migration was determined from the capacitor bodies thus obtained by the experimental configuration II described above. The time at which the current was increased to 2 mA was measured. The results are shown in Table 3.

[0307] Example 6:

[0308] Capacitors were prepared according to Preparation Example 8. After preparation, the capacitor bodies were immersed in an aqueous solution of 0.3 wt.% 5-methyl-1H-benzotriazole for 1 minute and then dried at 120°C for 10 minutes. Copper migration was determined from the capacitor bodies thus obtained by the experimental configuration II described above. The time at which the current was increased to 2 mA was measured. The results are shown in Table 3.

[0309] Example 7:

[0310] Capacitors were prepared according to Preparation Example 9. After preparation, the capacitor bodies were immersed in an aqueous solution of 0.3 wt.% 5-methyl-1H-benzotriazole for 1 minute and then dried at 120°C for 10 minutes. Copper migration was determined from the capacitor bodies thus obtained by the experimental configuration II described above. The time at which the current was increased to 2 mA was measured. The results are shown in Table 3.

[0311] Table 3:

[0312] Examples The time when the current reaches 2mA Comparative Example 1 10 seconds Example 2 210 seconds Example 3 >250 seconds Example 4 50 seconds Example 5 50 seconds Example 6 60 seconds Example 7 40 seconds

[0313] Copper dendrite growth can be significantly delayed by the metal migration inhibitor in the capacitors of Examples 2 to 7. After 10 seconds, a high DC current level of 2 mA was already observed in the absence of the metal migration inhibitor, due to the rapid copper dendrite growth. By adding the metal ion migration inhibitor to the capacitors of Examples 2 to 7, the time to reach 2 mA was significantly extended.

[0314] As can be seen, incorporating a metal ion migration inhibitor, such as 1,2,4-triazole or 5-methyl-1H-benzotriazole, into the solid electrolyte layer of a solid electrolyte capacitor comprising a conductive polymer such as polythiophene as a solid electrolyte material and a copper-containing anode lead frame, especially into the polymeric outer layer, causes a significant reduction in the migration of copper into the solid electrolyte layer, as shown in FIG. Figure 7 and Figure 8 As can also be seen from the results presented above, 5-methyl-1H-benzotriazole is even more effective than 1,2,4-triazole.

[0315] Example 8:

[0316] 0.3% of the metal ion migration inhibitor in Table 4 was mixed into the dispersion obtained in Preparation Example 3, applied to Experimental Configuration I (with the following slight modification: the distance between the two tips was set to 2 mm instead of 1 mm), and dried at 120° C. for 10 minutes. Copper migration was determined by the modified Experimental Configuration I.

[0317] Table 4:

[0318]

[0319] Copper dendrite growth was observed from the conductive polymer layer towards the copper strip. The absolute current level and the increase in current level over time correlated with the amount of copper dendrites and the rate of dendrite formation. The presence of the metal ion migration inhibitors mentioned in Table 4 in the conductive polymer layer significantly reduced copper dendrite formation compared to the conductive polymer layer not containing any metal migration inhibitor.

[0320] Unless otherwise specified in this specification or a specific drawing:

[0321] Figure 1 The basic structure of the tantalum capacitor 100 according to the present invention is shown in a cross-sectional view;

[0322] Figure 2 Shown in cross-section and enlarged view Figure 1 The structure of the electrode body 101 in the circled area shown in FIG.

[0323] Figure 3 The basic structure of the aluminum capacitor 100 according to the present invention is shown in a cross-sectional view;

[0324] Figure 4 The basic structure of a tantalum capacitor 100 according to the present invention is shown in a cross-sectional view, wherein the metal ion migration inhibitor is positioned within the solid electrolyte layer 103;

[0325] Figure 5 The basic structure of a tantalum capacitor 100 according to the invention is shown in cross section, wherein the metal ion migration inhibitor is positioned in the second solid electrolyte layer 103b (=polymeric outer layer);

[0326] Figure 6 The basic structure of the tantalum capacitor 100 according to the present invention is shown in a cross-sectional view, wherein the metal ion migration inhibitor is positioned between the first solid electrolyte layer 103a and the second solid electrolyte layer 103b;

[0327] Figure 7 Demonstration of the experimental configuration for determining copper ion migration I;

[0328] Figure 8 A. Figure 8 B shows the experimental setup II for measuring copper ion migration.

[0329] Figure 1 The basic structure of a tantalum capacitor 100 according to the present invention is shown in a cross-sectional view. The capacitor comprises an electrode body 101 comprising tantalum as an electrode material, wherein a dielectric layer 102 comprising tantalum oxide as a dielectric material at least partially covers a surface of the electrode body 101 (e.g., Figure 2 10). Tantalum wire 107 is introduced into electrode body 101 to allow electrical contact between electrode body 101 and anode contact 104. Capacitor 100 further comprises a solid electrolyte layer 103 at least partially covering the surface of dielectric layer 102, which comprises a solid electrolyte material, preferably PEDOT / PSS, PEDOT-S or a mixture thereof. Figure 1 It can also be seen that the solid electrolyte layer 103 is coated with a carbon layer 109, which in turn is coated with a silver layer 110. The capacitor 100 further comprises an anode contact 104, preferably in the form of an anode lead frame, which contacts the electrode body 101 via a tantalum wire 107, wherein the anode contact 104 comprises copper, metal-plated copper, or a copper-containing alloy. A cathode contact 105 is also provided, also preferably in the form of a cathode lead frame, which contacts the solid electrolyte layer 103 via a carbon layer 109 and a silver layer 110. Figure 1 It is also shown in FIG. 1 that an insulating layer 108 may be positioned on at least a portion of the surface of the tantalum wire 107, by which conductive contact between the tantalum wire 107 and the solid electrolyte layer 103, the carbon layer 109 and the silver layer 110 is avoided. The capacitor 100 is preferably embedded in a molded case 111.

[0330] Figure 1 The dashed box in indicates a region 106 between the anode contact 104 and the solid electrolyte layer 103, in which the solid electrolyte material is in close proximity to the copper-containing anode contact 104. Preferably, in the capacitor 100 according to the invention, at least one metal ion migration inhibitor is positioned in at least this region 106 between the anode contact 104 and the solid electrolyte layer 103, or within the solid electrolyte layer 103.

[0331] Figure 3 The basic structure of an aluminum capacitor 100 according to the present invention is shown in a cross-sectional view. Figure 1 The same basic structure of the tantalum capacitor 100 shown in FIG. 1 is shown, but includes an aluminum layer, preferably an etched aluminum foil, as an electrode body 101, on which a layer of aluminum oxide is deposited to form a dielectric layer 102. In addition, the aluminum layer is in direct contact with the anode contact 104. In a multilayer aluminum capacitor, several Figure 3 The structures shown in are stacked on top of each other.

[0332] Figures 4 to 6Different possibilities for the location of at least one metal ion migration inhibitor within a tantalum capacitor 100 according to the invention are shown, wherein the locations are indicated in black.

[0333] exist Figure 4 In the embodiment of the present invention, at least one metal ion migration inhibitor is positioned within the solid electrolyte layer 103. Such positioning can be achieved by using a solution or dispersion of a conductive polymer used to form the solid electrolyte layer 103, preferably a PEDOT / PSS dispersion, a PEDOT-S solution or a combination thereof, wherein such a dispersion and / or solution contains a certain amount of the metal ion migration inhibitor; or by impregnating a solid electrolyte layer 103 based on a conductive polymer such as PEDOT / PSS or PEDOT-S with the metal ion migration inhibitor (e.g., by using a solution or dispersion containing the metal ion migration inhibitor).

[0334] Figure 5 A capacitor 100 is shown in which the solid electrolyte layer comprises a first solid electrolyte layer 103a and a second solid electrolyte layer 103b acting as a polymeric outer layer, wherein at least one metal ion migration inhibitor is positioned within the second solid electrolyte layer 103b. Such positioning can also be achieved by using a solution or dispersion of a conductive polymer, preferably a PEDOT / PSS dispersion, for forming the second solid electrolyte layer 103b, which contains a certain amount of the metal ion migration inhibitor, or by impregnating the second solid electrolyte layer 103b based on PEDOT / PSS with the metal ion migration inhibitor.

[0335] Figure 6 A capacitor 100 is also shown, wherein the solid electrolyte layer comprises a first solid electrolyte layer 103a and a second solid electrolyte layer 103b, wherein at least one metal ion migration inhibitor is positioned in the region between the first solid electrolyte layer 103a and the second solid electrolyte layer 103b. Such positioning can be achieved if, for example, at least one metal ion migration inhibitor is added to a primer solution, which is typically used to coat the first solid electrolyte layer 103a with a primer layer 118 before applying the second solid electrolyte layer 103b, so as to improve the coverage of the first solid electrolyte layer 103a by a polymeric outer layer (as disclosed in WO-A-2010 / 089111), or by separately applying the metal ion migration inhibitor on top of the first solid electrolyte layer 103a.

[0336] Figure 7Experimental configuration I for determining copper ion migration is shown. A glass plate of size 25 mm×100 mm is used as a substrate. A polyimide film containing an arrow-shaped opening is deposited onto a substrate 112. Some droplets of a solid electrolyte dispersion are introduced into the opening. The polyimide mask is removed after the dispersion is dried, leaving an arrow-shaped conductive polymer layer 113 (simulating a solid electrolyte layer) on the substrate. An arrow-shaped copper tape 114 is glued to the substrate 112. The tip of the copper tape 114 and the tip of the conductive polymer layer 113 face each other. The distance between the two tips is set to 1 mm. A PTFE frame 115 is glued to the substrate 112, and the two tips are positioned at the center of the frame. The frame 115 is filled with 50 to 100 μl of deionized water 116 (simulating moisture that may accumulate during the operation of the capacitor in a humid atmosphere). A voltage of 20 VDC is applied between the conductive polymer layer and the copper tape, and the copper tape 114 is set as the anode and the arrow-shaped conductive polymer layer 113 is set as the cathode. The current was monitored over time after the voltage was applied.

[0337] Figure 8 A and Figure 8 B in Figure 1 shows an experimental configuration II that emulates experimental configuration I, with the difference that the conductive polymer layer is replaced by a tantalum capacitor. One edge of the tantalum capacitor 117 is positioned adjacent to the tip of the copper tape 114, with a distance of 1 mm. A PTFE frame 115 is glued to the substrate 112, and the tips of the tantalum capacitor 117 and the copper tape 114 are positioned in the center of the frame. The frame is filled with deionized water 116. A voltage of 20 VDC is applied between the solid electrolyte layer of the tantalum capacitor 117 and the copper tape 114, with the copper tape 114 set as the anode and the solid electrolyte layer set as the cathode. The current is monitored over time after the voltage is applied.

[0338] Component Symbol List

[0339] 100 Capacitor according to the present invention

[0340] 101 Electrode body

[0341] 102 Dielectric layer

[0342] 103 Solid Electrolyte Layer

[0343] 103a First solid electrolyte layer

[0344] 103b Second solid electrolyte layer

[0345] 104 Anode contact, preferably anode lead frame

[0346] 105 cathode contact, preferably cathode lead frame

[0347] 106 The region between the anode contact 104 and the solid electrolyte layer 103

[0348] 107 Tantalum Wire

[0349] 108 Insulation layer

[0350] 109 first conductive layer, preferably a carbon layer

[0351] 110 second conductive layer, preferably a silver layer

[0352] 111 Molded Shell

[0353] 112 Glass substrate

[0354] 113 Conductive polymer layer

[0355] 114 Copper Strip

[0356] 115PTFE tape

[0357] 116 Deionized water

[0358] 117 Tantalum capacitor with solid electrolyte layer

[0359] 118 base coat.

Claims

1. A capacitor (100), comprising i) an electrode body (101) comprising an electrode material, wherein a dielectric layer (102) comprising a dielectric material at least partially covers a surface of the electrode body (101); ii) a solid electrolyte layer (103) comprising a solid electrolyte material, which at least partially covers the surface of the dielectric layer (102), wherein the solid electrolyte material comprises a conductive polymer; iii) an anode contact (104) in contact with the electrode body (101) and comprising copper; and iv) a cathode contact (105) in contact with the solid electrolyte layer (103); The capacitor (100) further comprises at least one metal ion migration inhibitor capable of forming a chelate complex with copper ions, wherein the at least one metal ion migration inhibitor is positioned within the solid electrolyte layer (103) or on the surface of the solid electrolyte layer (103).

2. The capacitor (100) according to claim 1, wherein the anode contact (104) is in contact with the electrode body (101), and the anode contact (104) comprises metal-plated copper or a copper-containing alloy.

3. The capacitor (100) according to claim 1, wherein the solid electrolyte layer (103) comprises a first solid electrolyte layer (103a) after the dielectric layer (102) and a second solid electrolyte layer (103b) after the first solid electrolyte layer (103a), wherein the first solid electrolyte layer (103a) and the second solid electrolyte layer (103b) both comprise a conductive polymer as the solid electrolyte material.

4. The capacitor (100) according to claim 3, wherein at least one of the following conditions is satisfied: a) the at least one metal ion migration inhibitor is positioned within at least a portion of the first solid electrolyte layer (103a); b) the at least one metal ion migration inhibitor is positioned within at least a portion of the second solid electrolyte layer (103b); c) the at least one metal ion migration inhibitor is positioned on at least a portion of the surface of the first solid electrolyte layer (103a) facing the second solid electrolyte layer (103b); d) the at least one metal ion migration inhibitor is positioned on at least a portion of a surface of the second solid electrolyte layer (103b) facing away from the first solid electrolyte layer (103a).

5. The capacitor (100) according to any one of claims 1 to 3, wherein the conductive polymer is an exo-doped polythiophene, a self-doped polythiophene or a mixture thereof.

6. The capacitor (100) of any one of claims 1 to 3, wherein the at least one metal ion migration inhibitor is selected from the group consisting of azoles or derivatives thereof and oxazines or derivatives thereof.

7. The capacitor (100) of claim 6, wherein the azole is 5-methyl-1H-benzotriazole or a derivative thereof.

8. A method for producing a capacitor (100), comprising the following method steps: I) providing an electrode body (101) comprising an electrode material, wherein a dielectric layer (102) comprising a dielectric material at least partially covers a surface of the electrode material; II) depositing a solid electrolyte layer (103) comprising a solid electrolyte material onto at least a portion of the surface of the dielectric layer (102), wherein the solid electrolyte material comprises a conductive polymer; III) contacting the electrode body (101) with an anode contact (104) comprising copper; and IV) contacting the solid electrolyte layer (103) with a cathode contact (105); At least one metal ion migration inhibitor capable of forming a chelate complex with copper ions is introduced into the solid electrolyte layer (103) or applied to the surface of the solid electrolyte layer (103).

9. The method according to claim 8, wherein the anode contact (104) is in contact with the electrode body (101), the anode contact (104) comprising plated copper or a copper-containing alloy.

10. The method according to claim 8, wherein the step of depositing the solid electrolyte layer (103) onto at least a portion of the surface of the dielectric layer (102) in method step II) comprises the following steps: contacting the electrode body (101) obtained in method step I) with a liquid composition comprising the conductive polymer and at least one solvent followed by at least partial removal of the solvent, or with a monomer for preparing the conductive polymer and an oxidizing agent followed by in-situ polymerization of the monomer, or with a monomer for preparing the conductive polymer followed by electrochemical polymerization, to form the solid electrolyte layer (103); And wherein the at least one metal ion migration inhibitor is introduced into the solid electrolyte layer (103) or the at least one metal ion migration inhibitor is applied to the surface of this layer by: a) by adding the at least one metal ion migration inhibitor to the liquid composition comprising the conductive polymer, or to the monomer or the oxidizing agent used to prepare the conductive polymer; β) by contacting the solid electrolyte layer with a composition comprising the at least one metal ion transport inhibitor; or γ) is a combination of methods α) and β).

11. The method according to claim 8, wherein in method step II) a first solid electrolyte layer (103a) is deposited onto at least a portion of the surface of the dielectric layer (102), followed by a second solid electrolyte layer (103b) being deposited onto the first solid electrolyte layer (103a), wherein both the first solid electrolyte layer (103a) and the second solid electrolyte layer (103b) comprise a conductive polymer as the solid electrolyte material.

12. The method according to claim 11, wherein at least one of the following conditions is satisfied: A) during or after method step II), introducing the at least one metal ion transport inhibitor into the first solid electrolyte layer (103a); B) during or after method step II), introducing the at least one metal ion transport inhibitor into the second solid electrolyte layer (103b); C) during or after method step II), depositing the at least one metal ion migration inhibitor onto the surface of the first solid electrolyte layer (103a) facing the second solid electrolyte layer (103b); D) During or after method step II), the at least one metal ion transport inhibitor is deposited onto the surface of the second solid electrolyte layer (103b) facing away from the first solid electrolyte layer (103a).

13. The method of any one of claims 8 to 11, wherein the at least one metal ion transport inhibitor is 5-methyl-1H-benzotriazole or a derivative thereof.

14. An electronic circuit comprising a capacitor according to any one of claims 1 to 8.

15. Use of a capacitor according to any one of claims 1 to 8 in an electronic circuit.

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