Tantalum or niobium capacitor and preparation method and application thereof

Abstract

The invention belongs to the technical field of capacitors, and relates to a tantalum or niobium capacitor and a preparation method and application thereof, and the tantalum or niobium capacitor comprises a tantalum or niobium anode body, and a protection layer, an inner layer, a transition layer, an outer film layer and a conductive layer which sequentially coat the surface of the tantalum or niobium anode body from inside to outside; wherein the protective layer is formed by single impregnation of a pretreatment solution, the inner layer is formed by cyclic impregnation of an oxidant solution and a benzofuran diketone monomer solution, the transition layer is formed by repeated impregnation of a conductive polymer solution, and the outer film layer is formed by repeated impregnation of a conductive polymer-resin solution. The conductive layer comprises a conductive carbon layer or a conductive silver layer. The tantalum or niobium capacitor provided by the invention has the advantages of high extraction, low ESR and good heat resistance, is low in preparation difficulty and convenient to control, gives consideration to both production efficiency and production cost, and is beneficial to large-scale popularization and application.

Description

Technical Field

[0001] The present invention belongs to the technical field of capacitors, and relates to a tantalum or niobium capacitor, in particular to a tantalum or niobium capacitor, a preparation method thereof and an application thereof. Background Art

[0002] Tantalum or niobium capacitors are two important electrolytic capacitors. They use metallic tantalum or niobium as the positive electrode, a solution such as dilute sulfuric acid as the negative electrode, and an oxide film formed on the surface of tantalum or niobium as the dielectric. The advantages of these two capacitors are small volume, large capacitance, stable performance, long service life, large insulation resistance, good temperature characteristics, and relatively high capacitance density. They can provide a large capacitance in a small volume, and at the same time have high-energy, high-density, reliable and stable electrical performance.

[0003] The electrolyte of the existing tantalum or niobium capacitor is usually composed of MnO2 formed by the high-temperature decomposition of a manganese nitrate solution, or a polymer is used as the negative electrode material. However, the combination of the existing conductive polymer (poly(3,4-ethylenedioxythiophene)) and polystyrene sulfonate (PEDOT:PSS) has problems such as low conductivity, poor heat resistance and relatively high ESR, and there is still much room for improvement. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a tantalum or niobium capacitor, a preparation method thereof and an application thereof. The tantalum or niobium capacitor has the advantages of high lead-out, low ESR and good heat resistance, and has low preparation difficulty and convenient control, taking into account production efficiency and production cost, which is conducive to large-scale popularization and application.

[0005] To achieve the purpose of the present invention, the following technical solutions are adopted:

[0006] In the first aspect, the present invention provides a tantalum or niobium capacitor, which includes a tantalum or niobium anode body and a protective layer, an inner layer, a transition layer, an outer film layer and a conductive layer that are sequentially coated on the surface of the tantalum or niobium anode body from the inside to the outside.

[0007] Among them, the protective layer is formed by a single impregnation with a pretreatment solution, the inner layer is formed by a cyclic impregnation with an oxidant solution and a benzofurandione monomer solution, the transition layer is formed by repeated impregnation with a conductive polymer solution, the outer film layer is formed by repeated impregnation with a conductive polymer-resin solution, and the conductive layer includes a conductive carbon layer or a conductive silver layer.

[0008] The tantalum or niobium capacitor provided by the present invention forms a protective layer on the surface of the anode body by impregnation with a pretreatment solution, improving its leakage current and corrosion phenomenon, and effectively solving the surface adhesion problem; an inner layer is formed by cyclic impregnation with an oxidant solution and a benzofurandione monomer solution, and the benzofurandione monomer therein reacts and grows on the surface of the anode body to provide a carrier for the transition layer; based on the complex pore distribution of the anode body, in order to achieve cathode lead-out from the inside to the outside, a transition layer is formed by repeated impregnation with a conductive polymer solution to coat the anode body, fully supplementing the electrolyte, thereby further improving the lead-out rate; an outer membrane layer is formed by repeated impregnation with a conductive polymer-resin solution to endow the anode body with a certain strength, avoiding the phenomenon of loose shedding of the electrolyte of the tantalum or niobium capacitor; the obtained tantalum or niobium capacitor has the advantages of high lead-out, low ESR, and good heat resistance, and has low preparation difficulty, convenient control, taking into account production efficiency and production cost, and is conducive to large-scale popularization and application.

[0009] In a second aspect, the present invention provides a method for preparing a tantalum or niobium capacitor as described in the first aspect, and the preparation method includes the following steps:

[0010] (1) Placing the tantalum or niobium anode body in a pretreatment solution for single impregnation, and drying to obtain a tantalum or niobium anode body with a protective layer;

[0011] (2) Placing the tantalum or niobium anode body obtained in step (1) in an oxidant solution for first impregnation, and drying to obtain a first anode body;

[0012] (3) Placing the first anode body obtained in step (2) in a benzofurandione monomer solution for second impregnation, and drying to obtain a second anode body;

[0013] (4) Recording steps (2) and (3) as one cycle, and performing cyclic impregnation on the tantalum or niobium anode body to obtain a tantalum or niobium anode body with an inner layer;

[0014] (5) Placing the tantalum or niobium anode body obtained in step (4) in a conductive polymer solution for repeated impregnation, and drying to obtain a tantalum or niobium anode body with a transition layer;

[0015] (6) Placing the tantalum or niobium anode body obtained in step (5) in a conductive polymer-resin solution for repeated impregnation, and drying to obtain a tantalum or niobium anode body with an outer membrane layer;

[0016] (7) Performing carbon sealing treatment or silver sealing treatment on the tantalum or niobium anode body obtained in step (6) to obtain the tantalum or niobium capacitor.

[0017] In the present invention, the pretreatment solution in step (1) includes any one or a combination of at least two of a silane coupling agent solution, a polyacrylate solution, or a polyurethane solution.

[0018] In the present invention, the oxidant in the oxidant solution in step (2) includes any one or a combination of at least two of organic quinones, phosphomolybdic acid, peroxides, metal salts, persulfates, metal oxides, non-metal oxides, perborates or perbenzoic acid compounds.

[0019] In the present invention, the solvent in the oxidant solution in step (2) includes any one or a combination of at least two of dimethyl sulfoxide, ethanol, ethyl acetate, N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, deionized water, acetonitrile or propylene carbonate.

[0020] In the present invention, the benzofurandione monomer solution in step (3) includes benzofurandione monomers, resins, additives and solvents.

[0021] Among them, the benzofurandione monomers include 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione; the resins include any one or a combination of at least two of polyacrylate resins, polyurethane resins or polyester resins; the additives include any one or a combination of at least two of silane coupling agents, leveling agents, defoaming agents, adhesion promoters or ionic liquids; the solvents include dimethyl sulfoxide and / or N,N-dimethylacetamide.

[0022] In the present invention, the conductive polymer solution in step (5) includes any one or a combination of at least two of PBFDO-dimethyl sulfoxide solution, PBFDO-N,N-dimethylacetamide solution, PBFDO-N,N-dimethylformamide solution or PBFDO-N-methylpyrrolidone solution.

[0023] Among them, PBFDO refers to poly(benzofurandione).

[0024] In the present invention, the conductive polymer-resin solution in step (6) includes a conductive polymer solution and a film-forming resin.

[0025] Among them, the film-forming resins include any one or a combination of at least two of polyacrylate resins, polyurethane resins or epoxy resins.

[0026] In the present invention, the carbon sealing treatment in step (7) includes: placing a tantalum or niobium anode body with an outer film layer in a conductive carbon paste for a single impregnation, and drying to obtain a tantalum or niobium capacitor.

[0027] In the present invention, the silver sealing treatment in step (7) includes: placing a tantalum or niobium anode body with an outer film layer in a conductive silver paste for a single impregnation, and drying to obtain a tantalum or niobium capacitor.

[0028] In a third aspect, the present invention provides an application of the tantalum or niobium capacitor as described in the first aspect, and the tantalum or niobium capacitor is used in a filtering or energy storage circuit.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The tantalum or niobium capacitor provided by the present invention forms a protective layer on the surface of the anode body through impregnation with a pretreatment solution, which improves its leakage current and corrosion phenomenon, and effectively solves the surface adhesion problem; an inner layer is formed by cyclic impregnation with an oxidant solution and a benzofurandione monomer solution, and the benzofurandione monomer in it reacts and grows on the surface of the anode body to provide a carrier for the transition layer; based on the complex pore distribution of the anode body, in order to achieve cathode lead-out from the inside to the outside, a transition layer is formed by repeated impregnation with a conductive polymer solution to coat the anode body, fully supplementing the electrolyte, thereby further improving the lead-out rate; an outer membrane layer is formed by repeated impregnation with a conductive polymer-resin solution to endow the anode body with a certain strength, avoiding the phenomenon of loose shedding of the electrolyte of the tantalum or niobium capacitor; the obtained tantalum or niobium capacitor has the advantages of high lead-out, low ESR and good heat resistance, and has low preparation difficulty and convenient control, taking into account production efficiency and production cost, which is conducive to large-scale popularization and application. Description of the Drawings

[0031] Figure 1 is a schematic structural diagram of the tantalum or niobium capacitor provided by the present invention;

[0032] Figure 2 is a schematic diagram of the formation process of the protective layer in the tantalum capacitor provided in Example 1.

[0033] Wherein: 1 - tantalum or niobium anode body; 2 - protective layer; 3 - inner layer; 4 - transition layer; 5 - outer membrane layer; 6 - conductive layer. Detailed Embodiments

[0034] The technical solutions of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0035] An embodiment of the present invention provides a tantalum or niobium capacitor, as Figure 1 shown, the tantalum or niobium capacitor includes a tantalum or niobium anode body 1 and a protective layer 2, an inner layer 3, a transition layer 4, an outer membrane layer 5 and a conductive layer 6 that are sequentially coated on the surface of the tantalum or niobium anode body 1 from the inside to the outside.

[0036] Among them, the protective layer 2 is formed by a single impregnation with a pretreatment solution, the inner layer 3 is formed by cyclic impregnation with an oxidant solution and a benzofurandione monomer solution, the transition layer 4 is formed by repeated impregnation with a conductive polymer solution, the outer film layer 5 is formed by repeated impregnation with a conductive polymer-resin solution, and the conductive layer 6 includes a conductive carbon layer or a conductive silver layer.

[0037] The tantalum or niobium capacitor provided by the present invention forms a protective effect on the surface of the anode body through the protective layer 2 formed by impregnation with a pretreatment solution, improves its leakage current and corrosion phenomenon, and effectively solves the surface adhesion problem; the inner layer 3 is formed by cyclic impregnation with an oxidant solution and a benzofurandione monomer solution, and the benzofurandione monomer therein reacts and grows on the surface of the anode body to provide a carrier for the transition layer 4; based on the complex pore distribution of the anode body, in order to achieve cathode lead-out from the inside to the outside, the transition layer 4 is formed by repeated impregnation with a conductive polymer solution to coat the anode body, fully supplementing the electrolyte, thereby further improving the lead-out rate; the outer film layer 5 is formed by repeated impregnation with a conductive polymer-resin solution to endow the anode body with a certain strength, avoiding the phenomenon of loose shedding of the electrolyte of the tantalum or niobium capacitor; the obtained tantalum or niobium capacitor has the advantages of high lead-out, low ESR and good heat resistance, and has low preparation difficulty and convenient control, taking into account production efficiency and production cost, which is conducive to large-scale popularization and application.

[0038] An embodiment of the present invention also provides a preparation method for the tantalum or niobium capacitor described in any one of the above embodiments, and the preparation method includes the following steps:

[0039] (1) Place the tantalum or niobium anode body 1 in a pretreatment solution for single impregnation, and after drying, obtain the tantalum or niobium anode body 1 with the protective layer 2;

[0040] (2) Place the tantalum or niobium anode body 1 obtained in step (1) in an oxidant solution for the first impregnation, and after drying, obtain the first anode body;

[0041] (3) Place the first anode body obtained in step (2) in a benzofurandione monomer solution for the second impregnation, and after drying, obtain the second anode body;

[0042] (4) Denote steps (2) and (3) as one cycle, perform cyclic impregnation on the tantalum or niobium anode body 1, and obtain the tantalum or niobium anode body 1 with the inner layer 3;

[0043] (5) Place the tantalum or niobium anode body 1 obtained in step (4) in a conductive polymer solution for repeated impregnation, and after drying, obtain the tantalum or niobium anode body 1 with the transition layer 4;

[0044] (6) Place the tantalum or niobium anode body 1 obtained in step (5) in a conductive polymer-resin solution for repeated impregnation, and after drying, obtain the tantalum or niobium anode body 1 with the outer film layer 5;

[0045] (7) The tantalum or niobium anode body 1 obtained in step (6) is subjected to carbon sealing treatment or silver sealing treatment to obtain the tantalum or niobium capacitor.

[0046] In some embodiments, the pretreatment liquid in step (1) includes any one or a combination of at least two of a silane coupling agent solution, a polyacrylate solution, or a polyurethane solution. Typical but non-limiting combinations include a combination of a silane coupling agent solution and a polyacrylate solution, a combination of a polyacrylate solution and a polyurethane solution, a combination of a silane coupling agent solution and a polyurethane solution, or a combination of a silane coupling agent solution, a polyacrylate solution, and a polyurethane solution.

[0047] In some embodiments, the time for a single impregnation in step (1) is 0.5 - 3 min. For example, it can be 0.5 min, 1 min, 1.5 min, 2 min, 2.5 min, or 3 min, but is not limited to the listed values. Other unlisted values within this numerical range are equally applicable.

[0048] In some embodiments, the drying temperature in step (1) is 60 - 260 °C. For example, it can be 60 °C, 80 °C, 100 °C, 120 °C, 140 °C, 160 °C, 180 °C, 200 °C, 220 °C, 240 °C, or 260 °C, and the time is 8 - 15 min. For example, it can be 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min, or 15 min, but is not limited to the listed values. Other unlisted values within this numerical range are equally applicable.

[0049] In some embodiments, the oxidant in the oxidant solution in step (2) includes any one or a combination of at least two of organic quinones, phosphomolybdic acid, peroxides, metal salts, persulfates, metal oxides, non-metal oxides, perborates, or perbenzoic acid compounds. Typical but non-limiting combinations include a combination of organic quinones and phosphomolybdic acid, a combination of phosphomolybdic acid and peroxides, a combination of peroxides and metal salts, a combination of metal salts and persulfates, a combination of persulfates and metal oxides, a combination of metal oxides and non-metal oxides, a combination of non-metal oxides and perborates, or a combination of perborates and perbenzoic acid compounds.

[0050] In some embodiments, the concentration of the oxidant in the oxidant solution in step (2) is 2 - 50 mg / mL. For example, it can be 2 mg / mL, 5 mg / mL, 10 mg / mL, 15 mg / mL, 20 mg / mL, 25 mg / mL, 30 mg / mL, 35 mg / mL, 40 mg / mL, 45 mg / mL, or 50 mg / mL. However, it is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0051] In some embodiments, the solvent in the oxidant solution in step (2) includes any one or a combination of at least two of dimethyl sulfoxide, ethanol, ethyl acetate, N,N - dimethylacetamide, N,N - dimethylformamide, N - methylpyrrolidone, deionized water, acetonitrile, or propylene carbonate. Typical but non - limiting combinations include the combination of dimethyl sulfoxide and ethanol, the combination of ethanol and ethyl acetate, the combination of ethyl acetate and N,N - dimethylacetamide, the combination of N,N - dimethylacetamide and N,N - dimethylformamide, the combination of N,N - dimethylformamide and N - methylpyrrolidone, the combination of N - methylpyrrolidone and deionized water, the combination of deionized water and acetonitrile, or the combination of acetonitrile and propylene carbonate.

[0052] In some embodiments, the time for the first impregnation in step (2) is 0.5 - 3 min. For example, it can be 0.5 min, 1 min, 1.5 min, 2 min, 2.5 min, or 3 min. However, it is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0053] In some embodiments, the drying temperature in step (2) is 80 - 100 °C. For example, it can be 80 °C, 82 °C, 84 °C, 86 °C, 88 °C, 90 °C, 92 °C, ۹4 °C, 96 °C, 98 °C, or 100 °C, and the time is 8 - 45 min. For example, it can be 8 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, or 45 min. However, it is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0054] In some embodiments, the benzofurandione monomer solution in step (3) includes a benzofurandione monomer, a resin, an additive, and a solvent.

[0055] In some embodiments, the benzofurandione monomer includes 3,7 - dihydrobenzo[1,2 - b:4,5 - b']difuran - 2,6 - dione.

[0056] In certain embodiments, the concentration of the benzofurandione monomer in the solution is 4 - 16 mg / mL. For example, it can be 4 mg / mL, 6 mg / mL, 8 mg / mL, 10 mg / mL, 12 mg / mL, 14 mg / mL, or 16 mg / mL. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0057] In certain embodiments, the resin includes any one or a combination of at least two of polyacrylate resin, polyurethane resin, or polyester resin. Typical but non - limiting combinations include the combination of polyacrylate resin and polyurethane resin, the combination of polyurethane resin and polyester resin, the combination of polyacrylate resin and polyester resin, or the combination of polyacrylate resin, polyurethane resin, and polyester resin.

[0058] In certain embodiments, the concentration of the resin in the solution is ≤ 10 mg / mL. For example, it can be 1 mg / mL, 2 mg / mL, 3 mg / mL, 4 mg / mL, 5 mg / mL, 6 mg / mL, 7 mg / mL, 8 mg / mL, 9 mg / mL, or 10 mg / mL. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0059] In certain embodiments, the additives include any one or a combination of at least two of silane coupling agents, leveling agents, defoaming agents, adhesion promoters, or ionic liquids. Typical but non - limiting combinations include the combination of silane coupling agents and leveling agents, the combination of leveling agents and defoaming agents, the combination of defoaming agents and adhesion promoters, or the combination of adhesion promoters and ionic liquids.

[0060] In certain embodiments, the concentration of the additives in the solution is ≤ 4 mg / mL. For example, it can be 0.5 mg / mL, 1 mg / mL, 1.5 mg / mL, 2 mg / mL, 2.5 mg / mL, 3 mg / mL, 3.5 mg / mL, or 4 mg / mL. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0061] In certain embodiments, the solvent includes dimethyl sulfoxide and / or N,N - dimethylacetamide.

[0062] In certain embodiments, the time of the second impregnation in step (3) is 0.5 - 3 min. For example, it can be 0.5 min, 1 min, 1.5 min, 2 min, 2.5 min, or 3 min. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0063] In some embodiments, the temperature of the drying in step (3) is 90 - 130°C, for example, it can be 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C or 130°C, and the time is 8 - 45 min, for example, it can be 8 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min or 45 min, but it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0064] In some embodiments, the number of times of cyclic impregnation in step (4) is 1 - 4 times, for example, it can be 1 time, 2 times, 3 times or 4 times.

[0065] In some embodiments, the conductive polymer solution in step (5) includes any one or a combination of at least two of PBFDO - dimethyl sulfoxide solution, PBFDO - N,N - dimethylacetamide solution, PBFDO - N,N - dimethylformamide solution or PBFDO - N - methylpyrrolidone solution. Typical but non - limiting combinations include the combination of PBFDO - dimethyl sulfoxide solution and PBFDO - N,N - dimethylacetamide solution, the combination of PBFDO - N,N - dimethylacetamide solution and PBFDO - N,N - dimethylformamide solution, or the combination of PBFDO - N,N - dimethylformamide solution and PBFDO - N - methylpyrrolidone solution.

[0066] The conductive polymer used in the present invention has a relatively high conductivity (up to 2000 S / cm) and a relatively high thermal decomposition temperature (up to 380°C), which is beneficial to fully reduce the ESR and significantly improve the heat resistance of the capacitor.

[0067] In some embodiments, the solid content of the conductive polymer solution in step (5) is 2 - 15 mg / mL, for example, it can be 2 mg / mL, 3 mg / mL, 4 mg / mL, 5 mg / mL, 6 mg / mL, 7 mg / mL, 8 mg / mL, 9 mg / mL, 10 mg / mL, 11 mg / mL, 12 mg / mL, 13 mg / mL, 14 mg / mL or 15 mg / mL, but it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0068] In some embodiments, the number of times of repeated impregnation in step (5) is 3 - 7 times, for example, it can be 3 times, 4 times, 5 times, 6 times or 7 times. Drying is carried out after each impregnation, and the time for each impregnation is 0.5 - 3 min, for example, it can be 0.5 min, 1 min, 1.5 min, 2 min, 2.5 min or 3 min, but it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0069] In some embodiments, the temperature of the drying in step (5) is 80 - 120 °C, for example, it can be 80 °C, 85 °C, 90 °C, 95 °C, 100 °C, 105 °C, 110 °C, 115 °C or 120 °C, and the time is 8 - 45 min, for example, it can be 8 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min or 45 min, but it is not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0070] In some embodiments, the transition layer 4 in step (5) has a conductive polymer with a particle size of 10 - 60 nm, for example, it can be 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm or 60 nm, but it is not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0071] As previously mentioned, the conductive polymer solution in step (5) contains PBFDO. Since PBFDO is prone to crystallization and aggregation, the particle size of conventional PBFDO is higher than 200 nm, and this size is difficult to enter the micropores on the surface of the anode body to achieve the effect of improving the extraction rate. Therefore, the present invention specifically limits the particle size of the conductive polymer to 10 - 60 nm (<200 nm). The way to achieve this particle size range can be nanometer treatment, and the specific treatment conditions are not particularly limited herein.

[0072] In some embodiments, the conductive polymer - resin solution in step (6) includes a conductive polymer solution and a film - forming resin.

[0073] In some embodiments, the film - forming resin includes any one or a combination of at least two of polyacrylate resin, polyurethane resin or epoxy resin. Typical but non - limiting combinations include the combination of polyacrylate resin and polyurethane resin, the combination of polyurethane resin and epoxy resin, the combination of polyacrylate resin and epoxy resin, or the combination of polyacrylate resin, polyurethane resin and epoxy resin.

[0074] There is a synergistic effect between the film - forming resin and the conductive polymer solution adopted in the present invention, which is beneficial to supplement the electrolyte, can effectively wrap the tantalum or niobium anode body 1 and endow it with a certain strength, and further avoid the phenomenon that the electrolyte of the tantalum or niobium capacitor becomes loose and falls off.

[0075] Specifically, since the molecular chains of PBFDO in the conductive polymer solution are relatively rigid and prone to crystallization, the surface energy of the solvent used is relatively high, and the solid content of the solution is low. If used directly, shrinkage is likely to occur during the drying process, resulting in poor film-forming properties, weak adhesion, and inability to well wrap the device, thereby affecting the capacitance performance. The addition of the film-forming resin can effectively adjust the surface energy of the PBFDO solution, increase the solid content, and at the same time improve the flexibility of the material, thus improving the film-forming properties of the material and enhancing the adhesion of the film layer to the substrate.

[0076] In some embodiments, the addition amount of the film-forming resin is 1%-80% of the mass of the conductive polymer. For example, it can be 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or 80%, but is not limited to the listed values. Other unlisted values within this numerical range are equally applicable.

[0077] In some embodiments, the number of times of repeated impregnation in step (6) is 1-2 times. Drying is performed after each impregnation, and the time for each impregnation is 0.5-3 min. For example, it can be 0.5 min, 1 min, 1.5 min, 2 min, 2.5 min, or 3 min, but is not limited to the listed values. Other unlisted values within this numerical range are equally applicable.

[0078] In some embodiments, the drying temperature in step (6) is 80-120 °C. For example, it can be 80 °C, 85 °C, 90 °C, 95 °C, 100 °C, 105 °C, 110 °C, 115 °C, or 120 °C, and the time is 8-45 min. For example, it can be 8 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, or 45 min, but is not limited to the listed values. Other unlisted values within this numerical range are equally applicable.

[0079] In some embodiments, the carbon sealing treatment in step (7) includes: placing the tantalum or niobium anode body 1 with the outer film layer 5 in the conductive carbon paste for single impregnation, and drying to obtain a tantalum or niobium capacitor.

[0080] In some embodiments, the silver sealing treatment in step (7) includes: placing the tantalum or niobium anode body 1 with the outer film layer 5 in the conductive silver paste for single impregnation, and drying to obtain a tantalum or niobium capacitor.

[0081] In some embodiments, the single impregnation time for both the carbon sealing treatment and the silver sealing treatment in step (7) is 3 - 6 s, for example, it can be 3 s, 4 s, 5 s, or 6 s. The drying methods are natural air drying and blast drying in sequence. The natural air drying time is 20 min, and the blast drying temperature is 80 - 180 °C, for example, it can be 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, 170 °C, or 180 °C, and the time is 10 - 40 min, for example, it can be 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, or 40 min. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0082] Some embodiments of the present invention also provide an application of the tantalum or niobium capacitor described in any of the above embodiments. The tantalum or niobium capacitor is used in a filtering or energy storage circuit.

[0083] The numerical ranges described in the present invention include not only the above - listed point values but also any point values between the above - mentioned numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the described ranges.

[0084] Example 1

[0085] This example provides a tantalum capacitor and its preparation method. The preparation method includes the following steps:

[0086] (1) Place the tantalum anode body in the pretreatment solution for a single normal - pressure impregnation for 1 min, and dry it at 125 °C for 10 min to obtain a tantalum anode body with a protective layer 2. Among them, the pretreatment solution is an ethanol solution of silane coupling agent KH - 560 with a concentration of 5 mg / mL;

[0087] (2) Place the tantalum anode body obtained in step (1) in the oxidant solution for the first normal - pressure impregnation for 1 min, and dry it at 85 °C for 10 min to obtain the first anode body. Among them, the oxidant in the oxidant solution is 2,5 - dimethylbenzoquinone, the solvent is dimethyl sulfoxide, and the concentration is 20 mg / mL;

[0088] (3) The first anode body obtained in step (2) is placed in a benzofurandione monomer solution for a second atmospheric impregnation for 1 min, and then vacuum dried at 100 °C for 10 min to obtain a second anode body; wherein, the composition of the benzofurandione monomer solution is benzofurandione monomer, polymethyl acrylate (weight average molecular weight Mw is 50,000), silane coupling agent KH-570 and dimethyl sulfoxide solvent, and the benzofurandione monomer is specifically 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione, with a concentration of 10 mg / mL, the concentration of polymethyl acrylate is 3 mg / mL, and the concentration of silane coupling agent KH-570 is 0.5 mg / mL;

[0089] (4) Denote steps (2) and (3) as one cycle, and perform cyclic impregnation on the tantalum anode body 3 times to obtain a tantalum anode body with an inner layer 3;

[0090] (5) The tantalum anode body obtained in step (4) is placed in a conductive polymer solution for atmospheric impregnation for 1 min, and vacuum dried at 100 °C for 15 min, and then the impregnation and drying treatments are repeated 5 times to obtain a tantalum anode body with a transition layer 4; wherein, the conductive polymer solution is a PBFDO-dimethyl sulfoxide solution with a solid content of 8 mg / mL, and the transition layer 4 has a conductive polymer with a particle size of 40 nm;

[0091] (6) The tantalum anode body obtained in step (5) is placed in a conductive polymer-resin solution for atmospheric impregnation for 1 min, and vacuum dried at 100 °C for 15 min, and then the impregnation and drying treatments are repeated 2 times to obtain a tantalum anode body with an outer film layer 5; wherein, the conductive polymer-resin solution is composed of a conductive polymer solution and a film-forming resin, the components of the conductive polymer solution are the same as those in step (5), the film-forming resin is polymethyl acrylate (weight average molecular weight Mw is 120,000), and the addition amount is 30% of the mass of the conductive polymer;

[0092] (7) The tantalum anode body obtained in step (6) is placed in a uniformly stirred conductive carbon paste for a single atmospheric impregnation for 5 s, and then naturally dried for 20 min, and slowly inverted and rotated up and down during the drying process to ensure that the conductive carbon paste uniformly wraps the tantalum anode body. After drying is completed, it is baked in a blast oven at 150 °C for 15 min to obtain the tantalum capacitor.

[0093] The tantalum capacitor obtained through the above preparation method includes a tantalum anode body and a protective layer 2, an inner layer 3, a transition layer 4, an outer film layer 5, and a conductive layer 6 that are sequentially coated on the surface of the tantalum anode body from the inside to the outside.

[0094] Among them, the formation process of the protective layer 2 is shown in Figure 2, specifically: the silane coupling agent undergoes a hydrolysis reaction to form silanol, and then the obtained silanol undergoes a dehydration association reaction to bind to the surface of the tantalum anode body. At the same time, a cross-linking reaction occurs between the silane coupling agents, thereby forming a protective layer 2 on the surface of the tantalum anode body.

[0095] Example 2

[0096] This example provides a tantalum capacitor and a preparation method thereof. The preparation method includes the following steps:

[0097] (1) Place the tantalum anode body in a pretreatment solution for a single normal-pressure impregnation for 0.5 min, and dry it at 120 °C for 15 min to obtain a tantalum anode body with a protective layer 2; wherein, the pretreatment solution is an acetone solution of polymethyl acrylate (weight-average molecular weight Mw is 50,000), and the concentration is 5 mg / mL;

[0098] (2) Place the tantalum anode body obtained in step (1) in an oxidant solution for a first normal-pressure impregnation for 0.5 min, and dry it at 80 °C for 15 min to obtain a first anode body; wherein, the oxidant in the oxidant solution is copper acetate, the solvent is deionized water, and the concentration is 2 mg / mL;

[0099] (3) Place the first anode body obtained in step (2) in a benzofurandione monomer solution for a second normal-pressure impregnation for 0.5 min, and vacuum-dry it at 90 °C for 15 min to obtain a second anode body; wherein, the composition of the benzofurandione monomer solution is benzofurandione monomer, polymethyl acrylate (weight-average molecular weight Mw is 50,000), silane coupling agent KH-570 and dimethyl sulfoxide solvent, and the benzofurandione monomer is specifically 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione, the concentration is 4 mg / mL, the concentration of polymethyl acrylate is 1 mg / mL, and the concentration of silane coupling agent KH-570 is 0.2 mg / mL;

[0100] (4) Denote steps (2) and (3) as one cycle, and perform cyclic impregnation on the tantalum anode body 4 times to obtain a tantalum anode body with an inner layer 3;

[0101] (5) Place the tantalum anode body obtained in step (4) in a conductive polymer solution for a normal-pressure impregnation for 0.5 min, vacuum-dry it at 90 °C for 15 min, and then repeat the impregnation and drying treatments 7 times to obtain a tantalum anode body with a transition layer 4; wherein, the conductive polymer solution is a PBFDO-N-methylpyrrolidone solution with a solid content of 3 mg / mL, and the transition layer 4 has a conductive polymer with a particle size of 10 nm;

[0102] (6) The tantalum anode body obtained in step (5) is immersed in a conductive polymer-resin solution at normal pressure for 0.5 min, vacuum dried at 90 °C for 15 min, and then the impregnation and drying treatments are repeated 2 times to obtain a tantalum anode body with an outer film layer 5; wherein, the conductive polymer-resin solution is composed of a conductive polymer solution and a film-forming resin, the components of the conductive polymer solution are the same as those in step (5), the film-forming resin is polyacrylate resin (weight-average molecular weight Mw is 120,000), and the addition amount is 10% of the mass of the conductive polymer;

[0103] (7) The tantalum anode body obtained in step (6) is immersed in the uniformly stirred conductive carbon paste at normal pressure for a single time for 5 s, then air-dried naturally for 20 min, and slowly inverted and rotated up and down during the air-drying process to ensure that the conductive carbon paste uniformly wraps the tantalum anode body. After the air-drying is completed, it is baked in a blast oven at 150 °C for 15 min to obtain the tantalum capacitor.

[0104] The tantalum capacitor obtained through the above preparation method includes a tantalum anode body and a protective layer 2, an inner layer 3, a transition layer 4, an outer film layer 5, and a conductive layer 6 that are sequentially coated on the surface of the tantalum anode body from the inside to the outside.

[0105] Example 3

[0106] This example provides a tantalum capacitor and a preparation method thereof. The preparation method includes the following steps:

[0107] (1) The tantalum anode body is immersed in a pretreatment solution at normal pressure for a single time for 3 min, and dried at 200 °C for 8 min to obtain a tantalum anode body with a protective layer 2; wherein, the pretreatment solution is an ethanol solution of silane coupling agent KH-560 with a concentration of 5 mg / mL;

[0108] (2) The tantalum anode body obtained in step (1) is immersed in an oxidant solution at normal pressure for the first time for 3 min, and dried at 100 °C for 8 min to obtain a first anode body; wherein, the oxidant in the oxidant solution is potassium persulfate, the solvent is deionized water, and the concentration is 100 mg / mL;

[0109] (3) The first anode body obtained in step (2) is immersed in a benzofurandione monomer solution at normal pressure for the second time for 3 min, and vacuum dried at 120 °C for 8 min to obtain a second anode body; wherein, the composition of the benzofurandione monomer solution is benzofurandione monomer, polyurethane resin (weight-average molecular weight Mw is 30,000), silane coupling agent KH-570, and dimethyl sulfoxide solvent, and the benzofurandione monomer is specifically 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione with a concentration of 16 mg / mL, the concentration of polyurethane resin is 8 mg / mL, and the concentration of silane coupling agent KH-570 is 3 mg / mL;

[0110] (4) Denote steps (2) and (3) as one cycle, and perform cyclic impregnation on the tantalum anode body once to obtain a tantalum anode body with an inner layer 3;

[0111] (5) Place the tantalum anode body obtained in step (4) in a conductive polymer solution for atmospheric pressure impregnation for 3 min, vacuum dry at 120 °C for 8 min, and then repeat the impregnation and drying treatments 3 times to obtain a tantalum anode body with a transition layer 4; wherein, the conductive polymer solution is a PBFDO-N,N-dimethylacetamide solution with a solid content of 15 mg / mL, and the transition layer 4 has a conductive polymer with a particle size of 60 nm;

[0112] (6) Place the tantalum anode body obtained in step (5) in a conductive polymer-resin solution for atmospheric pressure impregnation for 3 min, vacuum dry at 120 °C for 8 min, and then repeat the impregnation and drying treatments once to obtain a tantalum anode body with an outer film layer 5; wherein, the conductive polymer-resin solution is composed of a conductive polymer solution and a film-forming resin, the components of the conductive polymer solution are the same as those in step (5), the film-forming resin is polyurethane resin (weight average molecular weight Mw is 80,000), and the addition amount is 50% of the mass of the conductive polymer;

[0113] (7) Place the tantalum anode body obtained in step (6) in a uniformly stirred conductive carbon paste for a single atmospheric pressure impregnation for 5 s, then air dry naturally for 20 min, and slowly invert and rotate up and down during the air drying process to ensure that the conductive carbon paste uniformly wraps the tantalum anode body. After the air drying is completed, bake in a blast oven at 150 °C for 15 min to obtain the tantalum capacitor.

[0114] The tantalum capacitor obtained by the above preparation method includes a tantalum anode body and a protective layer 2, an inner layer 3, a transition layer 4, an outer film layer 5, and a conductive layer 6 that are sequentially coated on the surface of the tantalum anode body from the inside to the outside.

[0115] Example 4

[0116] This example provides a niobium capacitor and a preparation method thereof. The preparation method includes the following steps:

[0117] (1) Place the niobium anode body in a pretreatment solution for a single atmospheric pressure impregnation for 2 min, and dry at 130 °C for 10 min to obtain a niobium anode body with a protective layer 2; wherein, the pretreatment solution is a butanone solution of polyurethane (weight average molecular weight Mw is 30,000) with a concentration of 5 mg / mL;

[0118] (2) The niobium anode body obtained in step (1) is placed in an oxidant solution for the first atmospheric impregnation for 2 min, dried at 85 °C for 9 min to obtain the first anode body; wherein, the oxidant in the oxidant solution is benzoyl peroxide, the solvent is ethanol, and the concentration is 10 mg / mL;

[0119] (3) The first anode body obtained in step (2) is placed in a benzofurandione monomer solution for the second atmospheric impregnation for 2 min, vacuum dried at 100 °C for 9 min to obtain the second anode body; wherein, the composition of the benzofurandione monomer solution is benzofurandione monomer, poly(methyl acrylate) (weight-average molecular weight Mw is 50000), silane coupling agent KH-570 and dimethyl sulfoxide solvent, and the benzofurandione monomer is specifically 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione, the concentration is 8 mg / mL, the concentration of poly(methyl acrylate) is 1 mg / mL, and the concentration of silane coupling agent KH-570 is 1 mg / mL;

[0120] (4) Denote steps (2) and (3) as one cycle, and perform cyclic impregnation on the niobium anode body 2 times to obtain a niobium anode body with an inner layer 3;

[0121] (5) The niobium anode body obtained in step (4) is placed in a conductive polymer solution for atmospheric impregnation for 2 min, vacuum dried at 100 °C for 9 min, and then the impregnation and drying treatments are repeated 4 times to obtain a niobium anode body with a transition layer 4; wherein, the conductive polymer solution is a PBFDO-dimethyl sulfoxide solution with a solid content of 10 mg / mL, and the transition layer 4 has a conductive polymer with a particle size of 40 nm;

[0122] (6) The niobium anode body obtained in step (5) is placed in a conductive polymer-resin solution for atmospheric impregnation for 2 min, vacuum dried at 100 °C for 9 min, and then the impregnation and drying treatments are repeated 2 times to obtain a niobium anode body with an outer film layer 5; wherein, the conductive polymer-resin solution is composed of a conductive polymer solution and a film-forming resin, the components of the conductive polymer solution are the same as those in step (5), the film-forming resin is poly(methyl acrylate) resin (weight-average molecular weight Mw is 120000), and the addition amount is 20% of the mass of the conductive polymer;

[0123] (7) The niobium anode body obtained in step (6) is placed in a uniformly stirred conductive carbon paste for a single atmospheric impregnation for 5 s, then naturally air-dried for 20 min, and slowly inverted and rotated up and down during the air-drying process to ensure that the conductive carbon paste uniformly wraps the niobium anode body. After air-drying is completed, it is baked in a blast oven at 150 °C for 15 min to obtain the niobium capacitor.

[0124] The niobium capacitor obtained through the above preparation method includes a niobium anode body and a protective layer 2, an inner layer 3, a transition layer 4, an outer film layer 5, and a conductive layer 6 that are sequentially coated on the surface of the niobium anode body from the inside to the outside.

[0125] Comparative Example 1

[0126] This comparative example provides a tantalum capacitor and a preparation method thereof. The preparation method includes the following steps:

[0127] (1) Immerse the tantalum anode body in the pretreatment solution for a single normal-pressure impregnation for 1 min, and dry it at 125 °C for 10 min to obtain a tantalum anode body with a protective layer 2. Among them, the pretreatment solution is an ethanol solution of silane coupling agent KH-560 with a concentration of 5 mg / mL;

[0128] (2) Immerse the tantalum anode body obtained in step (1) in the conductive polymer solution for a normal-pressure impregnation for 1 min, vacuum dry it at 100 °C for 15 min, and then repeat the impregnation and drying treatments 5 times to obtain a tantalum anode body with a transition layer 4. Among them, the conductive polymer solution is a PBFDO-dimethyl sulfoxide solution with a solid content of 8 mg / mL, and the transition layer 4 has a conductive polymer with a particle size of 40 nm;

[0129] (3) Immerse the tantalum anode body obtained in step (2) in the conductive polymer-resin solution for a normal-pressure impregnation for 1 min, vacuum dry it at 100 °C for 15 min, and then repeat the impregnation and drying treatments 2 times to obtain a tantalum anode body with an outer film layer 5. Among them, the conductive polymer-resin solution is composed of a conductive polymer solution and a film-forming resin. The components of the conductive polymer solution are the same as those in step (2), and the film-forming resin is poly(methyl acrylate) (weight-average molecular weight Mw is 120,000), and the addition amount is 30% of the mass of the conductive polymer;

[0130] (4) Immerse the tantalum anode body obtained in step (3) in the uniformly stirred conductive carbon paste for a single normal-pressure impregnation for 5 s, then air-dry it naturally for 20 min, and slowly invert and rotate it up and down during the air-drying process to ensure that the conductive carbon paste uniformly wraps the tantalum anode body. After air-drying is completed, bake it in a blast oven at 150 °C for 15 min to obtain the tantalum capacitor.

[0131] The tantalum capacitor obtained through the above preparation method includes a tantalum anode body and a protective layer 2, a transition layer 4, an outer film layer 5, and a conductive layer 6 that are sequentially coated on the surface of the tantalum anode body from the inside to the outside.

[0132] Comparative Example 2

[0133] This comparative example provides a tantalum capacitor and a preparation method thereof. The preparation method includes the following steps:

[0134] (1) Immerse the tantalum anode body in the pretreatment solution for a single atmospheric pressure impregnation for 1 min, and dry it at 125 °C for 10 min to obtain a tantalum anode body with a protective layer 2; wherein, the pretreatment solution is an ethanol solution of silane coupling agent KH-560 with a concentration of 5 mg / mL;

[0135] (2) Immerse the tantalum anode body obtained in step (1) in the oxidant solution for the first atmospheric pressure impregnation for 1 min, and dry it at 85 °C for 10 min to obtain the first anode body; wherein, the oxidant in the oxidant solution is ammonium persulfate, the solvent is deionized water, and the concentration is 50 mg / mL;

[0136] (3) Immerse the first anode body obtained in step (2) in the 3,4-ethylenedioxythiophene monomer solution for the second atmospheric pressure impregnation for 1 min, and vacuum dry it at 100 °C for 10 min to obtain the second anode body; wherein, the composition of the 3,4-ethylenedioxythiophene monomer solution is 3,4-ethylenedioxythiophene monomer, sodium polystyrenesulfonate (weight average molecular weight Mw is 100000), silane coupling agent KH-570 and ethanol solvent, and the concentration of 3,4-ethylenedioxythiophene monomer is 10 mg / mL, the concentration of sodium polystyrenesulfonate is 1 mg / mL, and the concentration of silane coupling agent KH-570 is 1 mg / mL;

[0137] (4) Denote steps (2) and (3) as one cycle, and perform cyclic impregnation on the tantalum anode body 3 times to obtain a tantalum anode body with an inner layer 3;

[0138] (5) Immerse the tantalum anode body obtained in step (4) in the conductive polymer solution for an atmospheric pressure impregnation for 1 min, vacuum dry it at 100 °C for 10 min, and then repeat the impregnation and drying treatment 5 times to obtain a tantalum anode body with a transition layer 4; wherein, the conductive polymer solution is a PEDOT:PSS-dimethyl sulfoxide solution with a solid content of 10 mg / mL, and the transition layer 4 has a conductive polymer with a particle size of 40 nm;

[0139] (6) Immerse the tantalum anode body obtained in step (5) in the conductive polymer-resin solution for an atmospheric pressure impregnation for 1 min, vacuum dry it at 100 °C for 10 min, and then repeat the impregnation and drying treatment 2 times to obtain a tantalum anode body with an outer film layer 5; wherein, the conductive polymer-resin solution is composed of a conductive polymer solution and a film-forming resin, the components of the conductive polymer solution are the same as those in step (5), the film-forming resin is poly(methyl acrylate) (weight average molecular weight Mw is 120000), and the addition amount is 30% of the mass of the conductive polymer;

[0140] (7) Place the tantalum anode body obtained in step (6) into the uniformly stirred conductive carbon paste for a single normal pressure impregnation for 5 s, then air-dry it naturally for 20 min, and slowly invert and rotate it up and down during the air-drying process to ensure that the conductive carbon paste uniformly wraps the tantalum anode body. After the air-drying is completed, bake it in a blast oven at 150 °C for 15 min to obtain the tantalum capacitor.

[0141] The tantalum capacitor obtained by the above preparation method includes a tantalum anode body and a protective layer 2, an inner layer 3, a transition layer 4, an outer film layer 5, and a conductive layer 6 that are sequentially coated on the surface of the tantalum anode body from the inside to the outside.

[0142] Comparative Example 3

[0143] This comparative example provides a tantalum capacitor and a preparation method thereof. The preparation method includes the following steps:

[0144] (1) Place the tantalum anode body into an oxidant solution for a first normal pressure impregnation for 1 min, and obtain a first anode body after drying at 85 °C for 10 min; wherein, the oxidant in the oxidant solution is 2,5-dimethylbenzoquinone, the solvent is dimethyl sulfoxide, and the concentration is 20 mg / mL;

[0145] (2) Place the first anode body obtained in step (1) into a benzofurandione monomer solution for a second normal pressure impregnation for 1 min, and obtain a second anode body after vacuum drying at 100 °C for 10 min; wherein, the composition of the benzofurandione monomer solution is a benzofurandione monomer, poly(methyl acrylate) (weight average molecular weight Mw is 50000), silane coupling agent KH-570, and dimethyl sulfoxide solvent, and the benzofurandione monomer is specifically 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione, the concentration is 10 mg / mL, the concentration of poly(methyl acrylate) is 3 mg / mL, and the concentration of silane coupling agent KH-570 is 0.5 mg / mL;

[0146] (3) Denote steps (1) and (2) as one cycle, and perform cyclic impregnation on the tantalum anode body 3 times to obtain a tantalum anode body with an inner layer 3;

[0147] (4) Place the tantalum anode body obtained in step (3) into a conductive polymer solution for a normal pressure impregnation for 1 min, vacuum dry it at 100 °C for 15 min, and then repeat the impregnation and drying treatments 5 times to obtain a tantalum anode body with a transition layer 4; wherein, the conductive polymer solution is a PBFDO-dimethyl sulfoxide solution with a solid content of 8 mg / mL, and the transition layer 4 has a conductive polymer with a particle size of 40 nm;

[0148] (5) The tantalum anode body obtained in step (4) is immersed in a conductive polymer-resin solution at normal pressure for 1 min, dried in vacuum at 100 °C for 15 min, and then the impregnation and drying treatments are repeated 2 times to obtain a tantalum anode body with an outer film layer 5; wherein, the conductive polymer-resin solution is composed of a conductive polymer solution and a film-forming resin, the components of the conductive polymer solution are the same as those in step (5), the film-forming resin is polymethyl acrylate (weight-average molecular weight Mw is 120,000), and the addition amount is 30% of the mass of the conductive polymer;

[0149] (6) The tantalum anode body obtained in step (5) is immersed in the uniformly stirred conductive carbon paste at normal pressure for a single time for 5 s, then naturally dried for 20 min, and slowly inverted and rotated up and down during the drying process to ensure that the conductive carbon paste uniformly wraps the tantalum anode body. After drying is completed, it is baked in a blast oven at 150 °C for 15 min to obtain the tantalum capacitor.

[0150] The tantalum capacitor obtained by the above preparation method includes a tantalum anode body and an inner layer 3, a transition layer 4, an outer film layer 5, and a conductive layer 6 that are sequentially coated on the surface of the tantalum anode body from the inside to the outside.

[0151] Performance test

[0152] The ZX8516B-1X series multi-parameter multi-frequency tester is used to test the tantalum or niobium capacitors obtained in Examples 1-4 and Comparative Examples 1-3 respectively, and the capacitance extraction rate, DF value, and ESR value of each capacitor are calculated and recorded. Among them, the capacitance extraction rate = actual measured capacitance CpY / standard capacitance × 100%.

[0153] The relevant test results are shown in Table 1 below.

[0154] Table 1

[0155] Tantalum or niobium capacitor Capacity extraction rate DF value (%) ESR value (mΩ) Example 1 87.3％ 2.1 11.62 Example 2 89.2％ 2.7 8.90 Example 3 84.6％ 3.6 13.95 Example 4 86.0％ 2.3 11.08 Comparative Example 1 20.12％ 15.2 35.17 Comparative Example 2 78.6％ 3.2 26.51 Comparative Example 3 80.5％ 4.3 13.57

[0156] It can be seen from Table 1 that: compared with Comparative Examples 1-3, the tantalum or niobium capacitors obtained in Examples 1-4 have a higher capacitance extraction rate, a lower ESR, and more excellent heat resistance.

[0157] It can be seen that the tantalum or niobium capacitor provided by the present invention forms a protective layer on the surface of the anode body by impregnation with a pretreatment solution, which improves its leakage current and corrosion phenomenon, and effectively solves the problem of surface adhesion; an inner layer is formed by cyclic impregnation of an oxidant solution and a benzofurandione monomer solution, and the benzofurandione monomer in it reacts and grows on the surface of the anode body to provide a carrier for the transition layer; based on the complex pore distribution of the anode body, in order to achieve cathode lead-out from the inside to the outside, a transition layer is formed by repeated impregnation with a conductive polymer solution to coat the anode body, fully supplementing the electrolyte, thereby further improving the lead-out rate; an outer membrane layer is formed by repeated impregnation with a conductive polymer-resin solution to endow the anode body with a certain strength, avoiding the phenomenon of loose shedding of the electrolyte of the tantalum or niobium capacitor; the obtained tantalum or niobium capacitor has the advantages of high lead-out, low ESR and good heat resistance, and has low preparation difficulty and convenient control, taking into account production efficiency and production cost, which is conducive to large-scale popularization and application.

[0158] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and disclosure scope of the present invention.

Claims

1. A tantalum or niobium capacitor, characterized in that, The tantalum or niobium capacitor includes a tantalum or niobium anode body, and a protective layer, an inner layer, a transition layer, an outer film layer, and a conductive layer that are sequentially coated on the surface of the tantalum or niobium anode body from the inside to the outside; Among them, the protective layer is formed by a single impregnation with a pretreatment solution, the inner layer is formed by a cyclic impregnation with an oxidant solution and a benzofurandione monomer solution, the transition layer is formed by repeated impregnation with a conductive polymer solution, the outer film layer is formed by repeated impregnation with a conductive polymer-resin solution, and the conductive layer includes a conductive carbon layer or a conductive silver layer.

2. A method for preparing a tantalum or niobium capacitor as described in claim 1, characterized in that, The preparation method includes the following steps: (1) Place the tantalum or niobium anode body in a pretreatment solution for single impregnation, and after drying, obtain a tantalum or niobium anode body with a protective layer; (2) Place the tantalum or niobium anode body obtained in step (1) in an oxidant solution for the first impregnation, and after drying, obtain a first anode body; (3) Place the first anode body obtained in step (2) in a benzofurandione monomer solution for the second impregnation, and after drying, obtain a second anode body; (4) Denote steps (2) and (3) as one cycle, and perform cyclic impregnation on the tantalum or niobium anode body to obtain a tantalum or niobium anode body with an inner layer; (5) Place the tantalum or niobium anode body obtained in step (4) in a conductive polymer solution for repeated impregnation, and after drying, obtain a tantalum or niobium anode body with a transition layer; (6) Place the tantalum or niobium anode body obtained in step (5) in a conductive polymer-resin solution for repeated impregnation, and after drying, obtain a tantalum or niobium anode body with an outer film layer; (7) Perform carbon sealing treatment or silver sealing treatment on the tantalum or niobium anode body obtained in step (6) to obtain the tantalum or niobium capacitor.

3. The preparation method according to claim 2, characterized in that, The pretreatment solution in step (1) includes any one or a combination of at least two of a silane coupling agent solution, a polyacrylate solution, or a polyurethane solution.

4. The preparation method according to claim 2, characterized in that, The oxidant in the oxidant solution in step (2) includes any one or a combination of at least two of organic quinones, phosphomolybdic acid, peroxides, metal salts, persulfates, metal oxides, non-metal oxides, perborates, or perbenzoic acid compounds; And / or, the solvent in the oxidant solution in step (2) includes any one or a combination of at least two of dimethyl sulfoxide, ethanol, ethyl acetate, N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, deionized water, acetonitrile, or propylene carbonate.

5. The preparation method according to claim 2, wherein The benzofurandione monomer solution in step (3) includes a benzofurandione monomer, a resin, an auxiliary agent, and a solvent; Among them, the benzofurandione monomer includes 3,7-dihydrobenz[1,2-b:4,5-b']difuran-2,6-dione; And / or, the resin includes any one or a combination of at least two of a polyacrylate resin, a polyurethane resin, or a polyester resin; And / or, the auxiliary agent includes any one or a combination of at least two of a silane coupling agent, a leveling agent, an antifoaming agent, an adhesion promoter, or an ionic liquid; And / or, the solvent includes dimethyl sulfoxide and / or N,N-dimethylacetamide.

6. The preparation method according to claim 2, wherein, The conductive polymer solution described in step (5) includes any one or a combination of at least two of PBFDO-dimethyl sulfoxide solution, PBFDO-N,N-dimethylacetamide solution, PBFDO-N,N-dimethylformamide solution, or PBFDO-N-methylpyrrolidone solution.

7. The preparation method according to claim 2, characterized in that, The conductive polymer-resin solution described in step (6) includes a conductive polymer solution and a film-forming resin; Among them, the film-forming resin includes any one or a combination of at least two of polyacrylate resin, polyurethane resin, or epoxy resin.

8. The preparation method according to claim 2, characterized in that, The carbon sealing treatment described in step (7) includes: placing a tantalum or niobium anode body with an outer film layer in a conductive carbon paste for single impregnation, and drying to obtain a tantalum or niobium capacitor.

9. The preparation method according to claim 2, characterized in that, The silver sealing treatment described in step (7) includes: placing a tantalum or niobium anode body with an outer film layer in a conductive silver paste for single impregnation, and drying to obtain a tantalum or niobium capacitor.

10. An application of the tantalum or niobium capacitor according to claim 1, characterized in that, The tantalum or niobium capacitor is used in a filtering or energy storage circuit.

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