Multilayer polymer capacitor based on n-type conductive polymer, and preparation method therefor

Abstract

Disclosed in the present application are a multilayer polymer capacitor based on an n-type conductive polymer, and a preparation method therefor. The preparation method comprises the following steps: acquiring a single capacitor having an oxide dielectric layer on the surface, cleaning and drying the surface of the single capacitor, impregnating same with a surface modifier solution, and then drying same, so as to obtain a surface-modified single capacitor; sequentially impregnating the surface-modified single capacitor with a polymerizable monomer solution and an oxidant solution, performing drying after each instance of impregnation, and repeating the process 6-10 times until an n-type conductive polymer film is formed; impregnating the single capacitor having the n-type conductive polymer film with an outer film layer solution, and heating and drying same to achieve the complete growth of an n-type conductive polymer on an oxide film; and impregnating same with a conductive carbon paste and a silver paste, and then laminating and extruding same, so as to obtain a multilayer polymer capacitor. While the equivalent series resistance of the multilayer polymer capacitor is reduced, the working stability of the multilayer polymer capacitor in a high-temperature and high-humidity environment is effectively improved.

Description

Chip-type laminated capacitor based on n-type conductive polymer and preparation method thereof TECHNICAL FIELD

[0001] The present application relates to the technical field of capacitors, in particular to a chip-type laminated capacitor based on n-type conductive polymer and a preparation method thereof. BACKGROUND

[0002] As one of the three major basic passive electronic components, capacitors play an important role in the electronic component industry and are one of the essential components in electronic circuits, accounting for about 56% of the global passive electronic component market. Capacitors are a kind of charge storage components made of two conductors close to each other and insulated from each other, which are mainly used for tuning, filtering, coupling, bypassing and energy conversion in circuits. Capacitors are mainly divided into four categories according to the different dielectrics, namely aluminum electrolytic capacitors, tantalum electrolytic capacitors, ceramic capacitors and thin film capacitors. Among them, aluminum electrolytic capacitors have the advantages of large capacity per unit volume, high voltage resistance, high cost performance, etc., and occupy more than 30% of the capacitor market share, and with the rapid development of new energy and consumer electronics industries, the proportion is on the rise. At high frequencies, the impedance curve of chip-type laminated polymer capacitors (MLPC) shows the characteristics of an ideal capacitor, and its capacitance is very stable under frequency changes, with the advantages of small size, good performance, wide temperature range, long service life, high reliability and high environmental protection, etc. It is a high-value-added high-performance product in aluminum electrolytic capacitors, suitable for the development trend of small size, high frequency, high speed, high reliability and high environmental protection of electronic products, and surface mount technology (SMT), and will become the focus of competition in the future aluminum electrolytic capacitor industry.

[0003] Chip type laminated polymer capacitor (MLPC) is a kind of aluminum electrolytic capacitor using conductive polymer as the actual cathode. Among them, the conductive polymer covers on the oxide film, which has important influence on the capacity extraction rate and the equivalent series resistance (ESR) of the capacitor. At present, the conductive polymer used in MLPC is usually p-type conductive polymer, including poly (3, 4-ethylenedioxythiophene) (PEDOT), polypyrrole and polyaniline, etc. The core technology is mainly controlled by Japanese manufacturers, which has become a "neck" problem in the field of Chinese high-end capacitor manufacturing. However, the use of PEDOT and other conductive polymers usually faces some inherent technical problems: 1) The equivalent series resistance (ESR) of the capacitor is mainly determined by the conductivity of the conductive polymer. At present, the conductivity of p-type conductive polymer has reached the limit value with the process upgrading. However, with the continuous updating of CPU and GPU chip performance, the operation speed is getting faster and faster, and the ESR value of the current product is difficult to meet the requirements of the next generation of server high-speed operation, which has become a major constraint factor for integrated circuits, and the industry urgently needs to find alternative materials or processes; 2) Since p-type conductive polymer is more prone to conduct positive charges, it is not matched in principle to use it as the cathode of the capacitor, which leads to poor high humidity and high temperature resistance of the existing MLPC product, short service life, and difficulty in meeting the long-term operation requirements of servers and 5G base stations.

[0004] Chinese patent CN116666115B discloses the use of n-type conductive polymer in electrolytic capacitor, which can significantly reduce the ESR of the capacitor and improve the stability of the capacitor. However, in MLPC, due to its more complex structure and process flow, simply using n-type conductive polymer solution is difficult to achieve complete filling and close coverage of the alumina pores. At the same time, there is a large contact resistance between the polymer and the oxide film, which restricts the further improvement of the performance and stability of MLPC. SUMMARY

[0005] The present application provides a preparation method of a chip type laminated capacitor based on n-type conductive polymer, which improves the working stability of MLPC in high temperature and high humidity environment, aiming at the problem that n-type conductive polymer is difficult to penetrate the oxide micropores and form a close coverage film on the oxide film in MLPC.

[0006] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] A preparation method of a chip type laminated capacitor based on n-type conductive polymer, comprising the following steps:

[0008] (1) Interface modification of capacitor monolithic: obtain a capacitor monolithic with an oxide medium layer on the surface, wash and dry the surface of the capacitor monolithic, then immerse the surface in a surface modifier solution, and then dry to obtain a surface modified capacitor monolithic;

[0009] (2) In-situ growth of n-type conductive polymer thin film on oxide thin film: the surface-modified capacitor sheet is sequentially immersed in polymer monomer solution and oxidant solution, and heated and dried after each immersion, and the steps of immersing in polymer monomer solution and oxidant solution are repeated 6-10 times until the n-type conductive polymer thin film is completely formed;

[0010] (3) Defect filling of n-type conductive polymer thin film: the capacitor sheet with preliminarily grown n-type conductive polymer thin film is immersed in outer film layer solution and heated and dried to achieve complete growth of n-type conductive polymer on the oxide film;

[0011] (4) Formation of carbon conductive layer: the capacitor sheet with deposited n-type conductive polymer is immersed in conductive carbon paste and dried to form a carbon conductive layer on the outer surface of the n-type conductive polymer;

[0012] (5) Lamination and extrusion: the capacitor sheet with carbon conductive layer formed on the outer surface of the n-type conductive polymer is immersed in silver paste, dried to form silver electrode, and connected between two or more capacitor sheets by silver glue, then laminated and extruded, and finally cut to obtain a chip-type multilayer capacitor.

[0013] The surface modifier solution comprises component F and component E;

[0014] The component F comprises units of alkoxy, phosphoric acid and carboxylic acid;

[0015] The units of alkoxy, phosphoric acid and carboxylic acid are selected from the following structures:

[0016] The units further comprise units of diketone groups or aldehyde groups;

[0017] The units of diketone groups or aldehyde groups are selected from the following structures:

[0018] Wherein, the wavy line represents the part bonded to other components;

[0019] The component E is a solvent selected from at least one of amide solvents, sulfoxide / sulfone solvents, alcohol solvents, ester solvents, alicyclic hydrocarbon solvents, alicyclic hydrocarbon solvents, halogenated hydrocarbon solvents, ether solvents and ketone solvents.

[0020] The capacitor sheet is prepared by the following method:

[0021] A plurality of aluminum sheets are welded on the same steel bar at an interval, and then the aluminum sheets are immersed in a formation solution for anodic oxidation to promote the formation of an aluminum oxide medium layer film.

[0022] The polymer monomer solution comprises component A and component B;

[0023] The component A is: benzo[1,2-b:4,5-b']difuran-2,6(3H,7H)-dione (cas: 30272-74-3);

[0024] The component B is a solvent; the solvent is selected from at least one of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, an alcohol solvent and an ester solvent;

[0025] The outer film layer solution comprises the component C, the component D and the component E;

[0026] The component C is poly(benzodifuran dione);

[0027] The component D is an oxidizing agent, the oxidizing agent is selected from at least one of an organic quinone, phosphomolybdic acid, a peroxide, a metal salt, a persulfate, a perborate and a perbenzoic acid compound;

[0028] The oxidizing agent solution comprises the component D and the component E.

[0029] The polymerized monomer solution further comprises poly(benzodifuran dione); the total concentration of the poly(benzodifuran dione) in the polymerized monomer solution is 0.5-5 mg / ml.

[0030] The polymerized monomer solution further comprises a binder, the binder comprises at least one of an epoxy resin and an acrylic resin, the concentration of the binder in the polymerized monomer solution is 0.5-2 mg / ml.

[0031] The concentration of the component F in the surface modifier solution is 0.2-10 mg / ml;

[0032] The concentration of the component A in the polymerized monomer solution is 10-25 mg / ml;

[0033] The concentration of the component C in the outer film layer solution is 5-15 mg / ml, and the total concentration of the component D is 0.2-5 mg / ml;

[0034] The total concentration of the component D in the oxidizing agent solution is 10-50 mg / ml.

[0035] The chemical conversion liquid is an aqueous solution of phosphoric acid with a concentration of 0.2-2 mg / ml and ammonium dihydrogen phosphate with a concentration of 1-10 mg / ml;

[0036] The number of laminated sheets of the capacitor monolithic is 2-12 sheets.

[0037] The drying method adopts one of vacuum drying and thermal annealing drying;

[0038] The drying temperature is 60-150 DEG C, and the drying time is 5-30 minutes.

[0039] The application also provides a n-type conductive polymer-based chip-type laminated capacitor prepared according to the preparation method.

[0040] Compared with the prior art, the main advantages of the application are as follows:

[0041] 1. The application is based on n-type conductive polymer poly(benzodifuran diketone), and the in-situ growth of the n-type conductive polymer on the dielectric is realized by pre-treating the oxide dielectric layer and using the in-situ polymerization method, so that the surface hydroxyl of the oxide dielectric layer is fully utilized, the oxide micropores can be effectively filled, the capacity can be effectively led out, and the stability of the interface contact can be ensured.

[0042] 2. The chip-type laminated polymer capacitor (MLPC) prepared according to the method of the application effectively makes up for the shortcomings of the existing material poly 3, 4-ethylenedioxythiophene: polystyrene sulfonate (PEDOT: PSS), reduces the ESR of the MLPC, and effectively improves the working stability of the MLPC in a high-temperature and high-humidity environment. BRIEF DESCRIPTION OF DRAWINGS

[0043] Other features, objects and advantages of the application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings:

[0044] Fig. 1 is a nuclear magnetic hydrogen spectrum diagram of compound 1 in deuterated chloroform in the embodiment 1 of the application;

[0045] Fig. 2 is a nuclear magnetic hydrogen spectrum diagram of compound 2 in deuterated dimethyl sulfoxide in the embodiment 2 of the application;

[0046] Fig. 3 is a flowchart and principle schematic diagram of the embodiment 1 of the application;

[0047] Fig. 4 is a scanning electron microscope morphology diagram of the polymer film layer on the aluminum foil in the embodiment 1 of the application with an amplification of 150 times;

[0048] Fig. 5 is a scanning electron microscope morphology diagram of the polymer film layer on the aluminum foil in the embodiment 1 of the application with an amplification of 500 times;

[0049] Fig. 6 is a cross-sectional view of the scanning electron microscope morphology diagram of the polymer film layer on the aluminum foil in the embodiment 1 of the application. DETAILED DESCRIPTION

[0050] The application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are intended to be illustrative only and are not in any way limiting to the scope of the present application. In addition, it should be understood that, for the purpose of clarity, only those parts of the drawings that are necessary for a full understanding of the present application are shown.

[0051] Poly(benzodifuran dione) (PBFDO) was purchased from Dongguan Fuan Optoelectronics Co., Ltd.

[0052] The application first prepares a surface modifier, and uses the prepared surface modifier compound to realize in-situ growth of n-type conductive polymer on a capacitor single piece. The preparation process and principle of the solid capacitor are shown in Figure 1: the oxide dielectric layer of the capacitor single piece is surface treated, then dried and dehydrated, and then sequentially immersed in a polymer monomer solution and an oxidizing agent solution, and then cycled multiple times, and finally immersed in an outer film layer solution, so as to grow an n-type conductive polymer film layer on the oxide dielectric layer substrate.

[0053] The application provides an in-situ growth method based on n-type conductive polymer material. The method can realize in-situ growth of n-type conductive polymer on an oxide substrate, has firm interface bonding force, low interface contact resistance, short process flow time, and good high temperature and high humidity stability, and can make up for the deficiencies of existing PEDOT and other p-type conductive polymers in the application of MLPC, and realize preparation of MLPC with low ESR and excellent stability.

[0054] The application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are intended to be illustrative only and are not in any way limiting to the scope of the present application. In addition, it should be understood that, for the purpose of clarity, only those parts of the drawings that are necessary for a full understanding of the present application are shown.

[0055] Example 1

[0056] (1) Preparation of compound 1:

[0057] Indole-2,3-dione (2.94 g, 20 mmol) was dissolved in 50 mL of N,N-dimethylformamide (DMF) under nitrogen protection to obtain a mixture; 60 wt% sodium hydride dispersed in kerosene (960 mg, 24 mmol) was added to the mixture, and after stirring at room temperature for 30 min, 2-bromoethyl diethyl phosphate (5.88 g, 24 mmol) was added; the reaction solution was continuously stirred at 80℃ for 5 h, and then cooled to room temperature; the solution was concentrated using a vacuum rotary evaporator, and the crude product was purified by column chromatography, with dichloromethane (DCM): ethyl acetate (EA) = 1:1 (by volume) as the eluent, to obtain an orange-red oily product (2.60 g, yield 40%); wherein the nuclear magnetic hydrogen spectrum of compound 1 is shown in Figure 2.

[0058] (2) Preparation of compound 2:

[0059] Compound 1 (2 g) obtained in step (1) was dissolved in 200 mL of dichloromethane (DCM) under nitrogen protection; trimethylsilyl bromide (3 g) was slowly added dropwise, and after stirring at 50°C for 24 hours, 200 mL of methanol was added; the reaction solution was continuously stirred at 50°C for 12 h, and then cooled to room temperature. The solution was concentrated to about 20 mL using a vacuum rotary evaporator, 100 mL of ether was added to precipitate the product, the product was collected by filtration, and further washed with ether for 3 times to obtain an orange-red solid (1.26 g, yield 76%). The nuclear magnetic resonance spectrum of hydrogen of compound 2 is shown in FIG. 3.

[0060] (3) A plurality of aluminum sheets are welded on the same steel strip at an interval distance, a part of each aluminum sheet is immersed in a chemical solution to perform anodic oxidation to promote the formation of an aluminum oxide medium layer on the surface of the aluminum sheet; the chemical solution is an aqueous solution of phosphoric acid with a concentration of 0.5 mg / ml and ammonium dihydrogen phosphate with a concentration of 5 mg / ml, each aluminum sheet is positioned by a glue line, and the part of each aluminum sheet below the glue line is below the liquid level of the chemical solution;

[0061] (4) The above aluminum sheets are washed with ethanol and dried at 150°C for 10 minutes; after the dried capacitor sheets are immersed in an ethanol solution of compound 2 with a concentration of 2 mg / ml for 5 minutes, they are dried at 150°C for 10 minutes to obtain surface-modified capacitor single sheets;

[0062] (5) The surface-modified capacitor single sheets are immersed in a polymer monomer solution for 1 minute and dried at 120°C for 5 minutes; then they are immersed in an oxidizing agent solution for 2 minutes and dried at 120°C for 5 minutes; the process of immersing the polymer monomer solution and the oxidizing agent solution is repeated for 10 times to realize in-situ growth of n-type conductive polymers on the outer surface of the aluminum oxide medium layer; the polymer monomer solution is a N,N-dimethylformamide (DMF) solution of benzo[1,2-b:4,5-b']difuran-2,6(3H,7H)-dione, and the concentration of benzo[1,2-b:4,5-b']difuran-2,6(3H,7H)-dione is 16 mg / ml; the oxidizing agent solution is a dimethyl sulfoxide solution of tetramethylbenzoquinone (cas:527-17-3), and the concentration of tetramethylbenzoquinone is 20 mg / ml;

[0063] (6) immerse the aluminum sheet with the n-type conductive polymer film preliminarily grown into the outer film layer solution for 1 minute, and heat dry at 100°C for 15 minutes to achieve complete growth of the n-type conductive polymer on the oxidation film; the outer film layer solution is a dimethyl sulfoxide solution of poly(benzodifuran-dione) and tetramethylbenzoquinone, wherein the concentration of poly(benzodifuran-dione) is 10 mg / ml, and the concentration of tetramethylbenzoquinone is 1 mg / ml. The conductive polymer film layer on the aluminum sheet is observed in morphology and cross section using a scanning electron microscope (SEM), as shown in FIG. 4, FIG. 5 and FIG. 6, and it can be seen that the smooth conductive polymer film layer can be formed on the surface of the aluminum foil by using the method of the present application.

[0064] (7) immerse the capacitor single sheet with the n-type conductive polymer deposited into the conductive carbon paste for 2 minutes, and heat dry at 150°C for 15 minutes after immersion to form a carbon conductive layer on the outer surface of the n-type conductive polymer;

[0065] (8) immerse the capacitor single sheet with the carbon conductive layer formed on the outer surface of the n-type conductive polymer into the silver paste for 2 minutes, and heat dry at 150°C for 15 minutes after immersion to achieve silver electrode formation;

[0066] (9) stack a plurality of the same capacitor single sheets immersed in the silver paste, the number of stacked sheets can be any number between 2 and 12, and the surface and side of the conductive silver layer on the capacitor single sheet are glued and stacked by extrusion using the conductive silver paste; the product after extrusion molding is cut and encapsulated into a finished product according to the existing process.

[0067] Example 2

[0068] (1) Preparation of compound 3:

[0069] Dissolve p-hydroxybenzaldehyde (2.44 g, 20 mmol) in 50 mL of N,N-dimethylformamide (DMF) under nitrogen protection to obtain a mixture; add 60 wt% sodium hydride dispersed in kerosene (960 mg, 24 mmol) to the mixture, stir at room temperature for 30 min, and then add 2-bromoethyl diethyl phosphate (5.88 g, 24 mmol); continue to stir at 80°C for 5 h, and then cool to room temperature; concentrate the solution using a vacuum rotary evaporator, and purify the crude product by column chromatography with dichloromethane (DCM): ethyl acetate (EA) = 1:1 (by volume) as the eluent to obtain the product compound 3 (3.72 g, yield 62%) in the form of colorless oil.

[0070] (2) Preparation of compound 4:

[0071] The compound 3 (2 g) obtained in step (1) was dissolved in 200 mL of dichloromethane (DCM) under nitrogen protection; trimethylsilyl bromide (3 g) was slowly added dropwise, and after stirring at room temperature for 24 hours, 200 mL of methanol was added; the reaction solution was continuously stirred at room temperature for 12 h. The solution was concentrated to about 20 mL using a vacuum rotary evaporator, 100 mL of ether was added to precipitate the product, the product was collected by filtration and further washed with ether for 3 times to obtain an orange-red solid compound 4 (1.30 g, yield 80%).

[0072] (3) The aluminum pieces were welded on the same steel strip at an interval distance, a part of all the aluminum pieces was immersed in the chemical solution to perform anodic oxidation to promote the formation of an aluminum oxide medium layer on the surface of the aluminum pieces; the chemical solution was an aqueous solution of phosphoric acid with a concentration of 0.2 mg / ml and ammonium dihydrogen phosphate with a concentration of 10 mg / ml, each aluminum piece was positioned by a glue line, and the part of each aluminum piece below the glue line was below the liquid level of the chemical solution;

[0073] (4) The above aluminum pieces were washed with ethanol and dried at 150°C for 10 minutes; after drying, the capacitor pieces were immersed in an ethanol solution of compound 2 with a concentration of 6 mg / ml for 5 minutes and then dried at 150°C for 10 minutes to obtain surface-modified capacitor pieces;

[0074] (5) The surface-modified capacitor pieces were immersed in a polymer monomer solution for 1 minute and dried at 120°C for 5 minutes; then they were immersed in an oxidizing agent solution for 2 minutes and dried at 120°C for 5 minutes; the process of immersing in the polymer monomer solution and the oxidizing agent solution was repeated for 10 times to realize in-situ growth of n-type conductive polymers on the outer surface of the aluminum oxide medium layer; the polymer monomer solution was a N,N-dimethylformamide (DMF) solution of benzo[1,2-b:4,5-b']difuran-2,6(3H,7H)-dione, and the concentration of benzo[1,2-b:4,5-b']difuran-2,6(3H,7H)-dione was 12 mg / ml; the oxidizing agent solution was a dimethyl sulfoxide solution of tetramethylbenzoquinone (cas:527-17-3), and the concentration of tetramethylbenzoquinone was 50 mg / ml;

[0075] (6) The aluminum pieces with a preliminary grown n-type conductive polymer film were immersed in an outer film layer solution for 1 minute and heated and dried at 100°C for 15 minutes to realize complete growth of n-type conductive polymers on the oxide film; the outer film layer solution was a dimethyl sulfoxide solution of poly(benzodifuran dione) and tetramethylbenzoquinone, and the concentration of poly(benzodifuran dione) was 5 mg / ml and the concentration of tetramethylbenzoquinone was 0.2 mg / ml.

[0076] (7) the capacitor monoplate on which the n-type conductive polymer is deposited is immersed in conductive carbon paste for 2 minutes, and after the immersion, the capacitor monoplate is heated and dried at 150°C for 15 minutes to form a carbon conductive layer on the outer surface of the n-type conductive polymer;

[0077] (8) the capacitor monoplate on which the carbon conductive layer is formed on the outer surface of the n-type conductive polymer is immersed in silver paste for 2 minutes, and after the immersion, the capacitor monoplate is heated and dried at 150°C for 15 minutes to achieve the formation of a silver electrode;

[0078] (9) a plurality of capacitor monoplates immersed in silver paste are stacked, the number of stacked monoplates can be any number in the range of 2-12, the surfaces and sides of the conductive silver layers on the capacitor monoplates are glued using conductive silver paste, and the stacked monoplates are extruded; the extruded product is cut and encapsulated according to the existing process to obtain a finished product.

[0079] Example 3

[0080] In this example, the in-situ growth of n-type conductive polymer on the capacitor monoplate is achieved using the compound 2 prepared in Example 1, and a part of the acrylate adhesive is additionally added to the polymer monomer solution to further improve the interlayer adhesion. The preparation process of the solid-state capacitor includes the following steps:

[0081] (1) a plurality of aluminum plates are welded on the same steel bar at an interval distance, a part of each aluminum plate is immersed in a formation solution to perform anodic oxidation to form an aluminum oxide medium layer on the surface of the aluminum plate; the formation solution is an aqueous solution of phosphoric acid with a concentration of 2 mg / ml and ammonium dihydrogen phosphate with a concentration of 2 mg / ml; each aluminum plate is positioned by a glue line, and the part below the glue line is below the liquid level of the formation solution;

[0082] (2) the above aluminum plates are washed with ethanol and dried at 80°C for 30 minutes; the dried capacitor plates are immersed in an ethanol solution of compound 2 with a concentration of 0.2 mg / ml for 5 minutes, and then dried at 150°C for 5 minutes to obtain the capacitor monoplate with a modified surface;

[0083] (3) the surface-modified capacitor single aluminum sheet is immersed in a polymer monomer solution for 5 minutes, dried at 80°C under vacuum for 10 minutes, immersed in an oxidant solution for 2 minutes, and dried at 80°C under vacuum for 10 minutes; the above process is repeated 8 times to achieve in-situ growth of n-type conductive polymer on the outer surface of the aluminum oxide medium layer; the polymer monomer solution is a mixed solution of N,N-dimethylformamide (DMF) solution of benzo[1,2-b:4,5-b']difuran-2,6(3H,7H)-dione (concentration of 16 mg / ml) and dimethyl sulfoxide (DMSO) solution of poly(benzodifuran dione) (concentration of 10 mg / ml) in a volume ratio of 4:1, and Romenhas acrylic resin PARALOID B-44 (concentration of 1 mg / ml) is added thereto; the oxidant solution is dimethyl sulfoxide solution of p-dimethylquinone (cas: 137-18-8), in which the concentration of p-dimethylquinone is 35 mg / ml.

[0084] (4) the aluminum sheet with the n-type conductive polymer film preliminarily grown thereon is further immersed in an outer film layer solution for 5 minutes, and heated and dried at 100°C for 15 minutes to achieve complete growth of the n-type conductive polymer on the oxide film; the outer film layer solution is dimethyl sulfoxide solution of poly(benzodifuran dione) and phosphomolybdic acid, in which the concentration of poly(benzodifuran dione) is 10 mg / ml and the concentration of phosphomolybdic acid is 0.5 mg / ml.

[0085] (5) the capacitor single with the n-type conductive polymer deposited thereon is immersed in carbon paste and silver paste in sequence, each for 2 minutes, and heated and dried at 150°C for 15 minutes after each immersion to obtain a capacitor single;

[0086] (6) 2-12 identical capacitor singles immersed in silver paste are stacked, the surface and side of the conductive silver layer on the capacitor single are glued using conductive silver paste, and the product after extrusion molding is cut and plastic-encapsulated into a finished product according to the existing process.

[0087] Example 4

[0088] (1) Preparation of compound 5:

[0089] Indole-2,3-dione (2.94 g, 20 mmol) was dissolved in 150 mL of acetonitrile under nitrogen protection to obtain a mixture; 60 wt% sodium hydride dispersed in kerosene (960 mg, 24 mmol) was added to the mixture, and after stirring at room temperature for 30 min, (3-iodopropyl)trimethoxysilane (6.96 g, 24 mmol) was added; after the reaction was continued to be stirred at 80°C for 5 h, it was cooled to room temperature; the solution was concentrated using a vacuum rotary evaporator, the crude product was dissolved in dichloromethane: petroleum ether = 4:1 (volume ratio) after filtration using diatomite, the filtrate was concentrated using a vacuum rotary evaporator to obtain the product in the form of an orange-red oil, which was washed using pure petroleum ether to obtain the product (3.83 g, yield 62%). The product was dissolved in ethyl acetate at 5 mg / ml for use in the next step.

[0090] (2) The aluminum pieces are welded on the same steel strip at an interval distance, a part of each aluminum piece is immersed in the chemical solution to perform anodic oxidation to promote the formation of an aluminum oxide medium layer on the surface of the aluminum piece; the chemical solution is an aqueous solution with a concentration of 1 mg / ml of phosphoric acid and 5 mg / ml of ammonium dihydrogen phosphate, each aluminum piece is positioned by an adhesive line, and the part below the adhesive line of each aluminum piece is placed below the liquid level of the chemical solution;

[0091] (3) The above aluminum pieces are washed with ethanol and dried at 150°C for 10 min; after the dried capacitor pieces are immersed in an ethyl acetate solution of compound 5 (concentration of 5 mg / ml) for 5 min, they are dried at 150°C for 10 min to obtain the surface-modified capacitor single piece;

[0092] (4) The surface-modified capacitor single piece is immersed in a polymer monomer solution, the polymer monomer solution is kept at 35-40°C, the immersion time is 4 min, and the drying is performed at 80°C under vacuum for 15 min; then the immersion time in the oxidant solution is 1 min, and the drying is performed at 80°C under vacuum for 15 min; the process of immersion in the polymer monomer solution and the oxidant solution is repeated for 6 times to realize the in-situ growth of n-type conductive polymer on the outer surface of the aluminum oxide medium layer; the polymer monomer solution is a N,N-dimethylacetamide (DMAc) solution of benzo[1,2-b:4,5-b']difuran-2,6(3H,7H)-dione (concentration of 20 mg / ml) containing an epoxy resin (concentration of 0.5 mg / ml); the oxidant solution is a dimethyl sulfoxide solution of tetramethylbenzoquinone (cas:527-17-3) and iron p-toluenesulfonate (cas:77214-82-5) (concentration of tetramethylbenzoquinone is 20 mg / ml, and concentration of iron p-toluenesulfonate is 1 mg / ml); when the process of immersion in the polymer monomer solution and the oxidant solution is 6 or 7 times, the temperature of the heated polymer monomer solution is 35-40°C, so that each capacitor piece can grow some n-type conductive polymer during immersion, thereby reducing the number of immersions.

[0093] (5) immerse the aluminum sheet with the n-type conductive polymer thin film preliminarily grown into an outer film layer solution for 2 minutes, and heat dry at 60°C under vacuum for 30 minutes to achieve complete growth of the n-type conductive polymer on the oxide film; the outer film layer solution is a dimethyl sulfoxide solution of poly(benzodifuran-dione) and tetramethylbenzoquinone, copper acetate, wherein the concentration of poly(benzodifuran-dione) is 15 mg / ml, the concentration of tetramethylbenzoquinone is 1 mg / ml, and the concentration of copper acetate is 0.1 mg / ml.

[0094] (6) immerse the capacitor sheet with the n-type conductive polymer deposited into conductive carbon paste for 2 minutes, and heat dry at 150°C for 15 minutes after immersion to form a carbon conductive layer on the outer surface of the n-type conductive polymer;

[0095] (7) immerse the capacitor sheet with the carbon conductive layer formed on the outer surface of the n-type conductive polymer into silver paste for 2 minutes, and heat dry at 150°C for 15 minutes after immersion to achieve silver electrode formation;

[0096] (8) stack 4 identical capacitor sheets immersed in silver paste, use conductive silver paste to glue the surface and side of the conductive silver layer on the capacitor sheet, and perform layering and extrusion; cut the extruded product, and perform plastic packaging according to the existing process to obtain a finished product.

[0097] Example 5

[0098] (1) Preparation of compound 6:

[0099] Indole-2,3-dione (2.94 g, 20 mmol) was dissolved in 50 mL of N,N-dimethylformamide (DMF) under nitrogen protection to obtain a mixture; 60 wt% sodium hydride dispersed in kerosene (960 mg, 24 mmol) was added to the mixture, and after stirring at room temperature for 30 min, 6-chloromethyl hexyl acrylate (4.90 g, 24 mmol) was added; the reaction solution was continuously stirred at 80°C for 5 h, and then cooled to room temperature; the solution was concentrated using a vacuum rotary evaporator, and the crude product was purified by column chromatography with dichloromethane (DCM): petroleum ether (PE) = 1:1 (volume ratio) as the eluent to obtain an orange-red oily product (1.64 g, yield 26%).

[0100] (2) Preparation of compound 7:

[0101] Compound 5 (2.0 g) and 3-(trimethoxysilyl)propyl methacrylate (0.2 g) were dissolved in 50 mL of dioxane under nitrogen protection, and 50 mg of azobisisobutyronitrile (AIBN) was added. After the reaction mixture was stirred at 80°C for 24 hours, it was cooled to room temperature. The reaction solution was loaded into a pre-treated 1000 Da dialysis bag, and dialysis was performed using dioxane for 24 hours. The solution in the dialysis bag was collected, and dioxane was added to dilute it to a compound 6 solution with a solid content of 10 mg / ml for standby use. The molecular weight of compound 6 was determined by gel permeation chromatography, Mn = 8.2 kDa, PDI = 2.17.

[0102] (3) The multiple aluminum pieces are welded on the same steel strip at an interval distance, a part of each aluminum piece is immersed in the formation solution to perform anodic oxidation to form an aluminum oxide medium layer on the surface of the aluminum piece; the formation solution is an aqueous solution with a phosphoric acid concentration of 0.5 mg / ml and ammonium dihydrogen phosphate of 5 mg / ml; each aluminum piece is positioned by an adhesive line, and the lower part of the adhesive line is below the liquid level of the formation solution;

[0103] (4) The above aluminum piece is washed with ethanol and dried at 150°C for 10 minutes; the dried capacitor piece is placed in a dioxane solution of compound 7 with a concentration of 5 mg / ml, immersed for 5 minutes, and then dried at 150°C for 10 minutes to obtain a surface-modified capacitor single piece;

[0104] (5) The surface-modified capacitor single piece is immersed in a polymer monomer solution for 5 minutes, the polymer monomer solution is heated to 40°C during the immersion, and then dried at 120°C for 5 minutes; then it is immersed in an oxidizing agent solution for 0.5 minutes and dried at 120°C for 5 minutes; the process of immersing the polymer monomer solution and the oxidizing agent solution is repeated for 7 times to realize in-situ growth of n-type conductive polymer on the outer surface of the aluminum oxide medium layer; the polymer monomer solution is a mixed solution obtained by mixing a N,N-dimethylacetamide (DMAc) solution of benzo[1,2-b:4,5-b']difuran-2,6(3H,7H)-dione (concentration of 20 mg / ml) and a dimethyl sulfoxide (DMSO) solution of poly(benzodifuran-dione) (concentration of 10 mg / ml) at a volume ratio of 3:1; the oxidizing agent solution is a mixed solution obtained by mixing a dimethyl sulfoxide solution of tetramethylbenzoquinone (cas:527-17-3) and copper acetate (cas:142-71-2) and a N,N-dimethylacetamide solution of tetramethylbenzoquinone (cas:527-17-3) and copper acetate (cas:142-71-2) at a volume ratio of 2:1, wherein the concentration of tetramethylbenzoquinone is 16 mg / ml, and the concentration of copper acetate is 2 mg / ml.

[0105] (6) immerging the aluminum sheet with the n-type conductive polymer thin film preliminarily grown on the surface of the aluminum sheet into an outer film layer solution, and heating and drying at 100°C for 15 minutes to completely grow the n-type conductive polymer on the oxide film; the outer film layer solution is a dimethyl sulfoxide solution of poly(benzodifuran-dione) and tert-butyl hydroperoxide, wherein the concentration of poly(benzodifuran-dione) is 10 mg / ml, and the concentration of tert-butyl hydroperoxide is 0.5 mg / ml.

[0106] (7) immerging the capacitor sheet with the n-type conductive polymer deposited thereon into a conductive carbon paste, and immerging for 2 minutes, and then heating and drying at 150°C for 15 minutes to form a carbon conductive layer on the outer surface of the n-type conductive polymer;

[0107] (8) immerging the capacitor sheet with the carbon conductive layer formed on the outer surface of the n-type conductive polymer into a silver paste, and immerging for 2 minutes, and then heating and drying at 150°C for 15 minutes to form a silver electrode;

[0108] (9) stacking 4 or 8 identical capacitor sheets immerged into the silver paste, and dispensing conductive silver paste on the surface and side of the conductive silver layer on the capacitor sheet, and then performing layering and extrusion; cutting the extruded product, and then performing plastic packaging according to the existing process to obtain a finished product.

[0109] Comparative Example 1

[0110] In this comparative example, a commonly used p-type conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) is used as the polymer layer on the aluminum sheet, which is used to compare and illustrate the performance superiority of the n-type conductive polymer in-situ growth method on the oxide film dielectric layer and the corresponding sheet type stacked polymer capacitor disclosed in the present application. The preparation process comprises the following steps:

[0111] (1) welding a plurality of aluminum sheets on the same steel strip at an interval distance, and immersing a part of each aluminum sheet into a formation solution to perform anodic oxidation and form an aluminum oxide dielectric layer on the surface of the aluminum sheet; the formation solution is a phosphoric acid solution with a concentration of 0.5 mg / ml and an ammonium dihydrogen phosphate aqueous solution with a concentration of 5 mg / ml; each aluminum sheet is positioned by a glue line, and the part below the glue line is placed below the liquid level of the formation solution;

[0112] (2) immersing the aluminum sheet into a polymer monomer solution, and then immersing into an oxidant solution, and then drying at 50°C for 10 minutes; repeating the above process for 20 times to realize in-situ growth of the p-type conductive polymer on the outer surface of the aluminum oxide dielectric layer; the polymer monomer solution is an ethanol solution of 3,4-ethylenedioxythiophene (cas: 126213-50-1) with a concentration of 50 mg / ml; the oxidant solution is a ferric p-toluenesulfonate (cas: 312619-41-3) aqueous solution with a concentration of 50 mg / ml.

[0113] (3) The aluminum sheet of step (2) is immersed in a commercially available PEDOT:PSS solution for 5 minutes, and dried at 140°C for 30 minutes;

[0114] (4) The aluminum sheet of step (3) is sequentially immersed in carbon paste and silver paste, each for 2 minutes, and heated and dried at 150°C for 15 minutes after each immersion, to obtain a capacitor single sheet.

[0115] (5) Multiple identical capacitor single sheets immersed in silver paste are stacked, the surface and side of the conductive silver layer on the capacitor single sheet are glued with conductive silver paste, and then stacked and extruded; the extruded product is cut and encapsulated into a finished product according to the existing process.

[0116] Comparative Example 2

[0117] This comparative example directly uses n-type conductive polymer poly(benzodifuran dione) as the polymer layer on the aluminum sheet, for comparison to illustrate the performance superiority of the in-situ growth method of n-type conductive polymer on the oxide film dielectric layer and the corresponding sheet-type stacked polymer capacitor disclosed in the present application. The preparation process comprises the following steps:

[0118] (1) Multiple aluminum sheets are spaced welded on the same steel bar, and a part of each aluminum sheet is immersed in a formation solution to perform anodic oxidation to form an aluminum oxide dielectric layer on the surface of the aluminum sheet; the formation solution is an aqueous solution with a phosphoric acid concentration of 0.5 mg / ml and an ammonium dihydrogen phosphate concentration of 5 mg / ml; the aluminum sheet is positioned by an adhesive line, and the part below the adhesive line is placed below the liquid level of the formation solution;

[0119] (2) The aluminum sheet obtained in step (1) is immersed in a dimethyl sulfoxide (DMSO) solution of poly(benzodifuran dione) (concentration of 10 mg / ml) for 10 minutes, and dried at 120°C for 10 minutes; the above steps are repeated 6 times to form a complete polymer film;

[0120] (3) The aluminum sheet obtained in step (2) is further sequentially immersed in carbon paste and silver paste, each for 2 minutes, and heated and dried at 150°C for 15 minutes after each immersion, to obtain a capacitor single sheet.

[0121] (4) Multiple identical capacitor single sheets are stacked, the surface and side of the conductive silver layer on the capacitor single sheet are glued with conductive silver paste, and then stacked and extruded; the extruded product is cut and encapsulated into a finished product according to the existing process.

[0122] Test Example 1

[0123] The performance of the capacitor monopieces prepared in Examples 1-5 and Comparative Examples 1-2 was tested, and the test results are shown in Table 1. It can be seen that the capacitor monopieces prepared based on the present application have higher capacity and lower equivalent series resistance (ESR) than the monopieces prepared based on the existing p-type conductive polymer process, under the premise of using the same aluminum foil. Meanwhile, the in-situ growth method of n-type conductive polymer proposed in the present application can solve the problem that the existing n-type conductive polymer is difficult to enter the micropores of the oxide film, and realize capacity extraction.

[0124] Table 1

[0125] Test Example 2

[0126] The performance of the chip-type laminated polymer capacitors prepared from the capacitor monopieces prepared in Examples 1-5 and Comparative Example 1 was tested, and the test results are shown in Table 2. The chip-type laminated polymer capacitors were prepared by laminating 4 capacitor monopieces. It can be seen that the chip-type laminated polymer capacitors prepared based on the present application have lower equivalent series resistance (ESR) than the chip-type laminated polymer capacitors prepared based on the existing p-type conductive polymer process, under the premise of using the same lamination process.

[0127] Table 2

[0128] Test Example 3

[0129] The stability of the chip-type laminated polymer capacitors prepared from the capacitor monopieces prepared in Examples 1-5 and Comparative Example 1 was tested, and the test results are shown in Table 3. It can be seen that the chip-type laminated polymer capacitors prepared based on the present application have obvious advantages in high-temperature long-term stability compared to the chip-type laminated polymer capacitors prepared based on the existing p-type conductive polymer process, and the performance decay of ESR and capacity is obviously inhibited under high-temperature load environment.

[0130] Table 3

[0131] The above description is merely preferred embodiments of the present application and a description of the principles of the technology used. Those skilled in the art should understand that the scope of the application disclosed in the present application is not limited to the technical solutions formed by the specific combinations of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or equivalent features, without departing from the inventive concept. For example, the above features can be replaced with technical features disclosed in the present application (but not limited to) having similar functions to form technical solutions.

Claims

1. A method for producing a chip-type laminated capacitor based on an n-type conductive polymer, characterized by, The method comprises the following steps: (1) Interface modification of the capacitor monolithic piece: obtain a capacitor monolithic piece with an oxide medium layer on the surface, clean and dry the surface of the capacitor monolithic piece, immerse the surface in a surface modifier solution, and then dry to obtain a surface-modified capacitor monolithic piece; (2) In-situ growth of an n-type conductive polymer film on the oxide film: immerse the surface-modified capacitor monolithic piece in a polymer monomer solution and an oxidizing agent solution in sequence, dry after each immersion, and repeat the steps of immersing the polymer monomer solution and the oxidizing agent solution for 6-10 times until the n-type conductive polymer film is completely formed; (3) Defect filling of the n-type conductive polymer film: immerse the capacitor monolithic piece with the preliminarily grown n-type conductive polymer film in an outer film layer solution and dry to completely grow the n-type conductive polymer on the oxide film; (4) Formation of a carbon conductive layer: immerse the capacitor monolithic piece with the deposited n-type conductive polymer in a conductive carbon paste, dry, and form a carbon conductive layer on the outer surface of the n-type conductive polymer; (5) Lamination and extrusion: immerse the capacitor monolithic piece with the carbon conductive layer on the outer surface of the n-type conductive polymer in silver paste, dry, form silver electrodes, connect two or more capacitor monolithic pieces with silver glue, and then perform lamination and extrusion, and finally cut to obtain a chip-type multilayer capacitor; The surface modifier solution comprises component F and component E; The component F comprises units of alkoxy, phosphoric acid or carboxylic acid; The alkoxyl, phosphonic or carboxylic acid units are selected from the following structures: The component F further comprises units of diketone groups or aldehyde groups; The diketone group or aldehyde group unit is selected from the following structures: The wavy line represents a part connected to other components; The component E is a solvent selected from at least one of amide solvents, sulfoxide / sulfone solvents, alcohol solvents, ester solvents, alicyclic hydrocarbon solvents, halogenated hydrocarbon solvents, ether solvents and ketone solvents; The polymer monomer solution comprises component A and component B; The component A is benzo[1,2-b:4,5-b']difuran-2,6(3H,7H)-dione (cas: 30272-74-3); The component B is a solvent selected from at least one of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, alcohol solvents and ester solvents; The outer film layer solution comprises component C, component D and the component E; The component C is poly(benzodifuran dione); The component D is an oxidizing agent selected from at least one of organic quinones, phosphomolybdic acid, peroxides, metal salts, persulfates, perborates and perbenzoic acid compounds; The oxidizing agent solution comprises the component D and the component E.

2. The production method according to claim 1, characterized by, The capacitor monolithic piece is prepared by the following method: Weld a plurality of aluminum pieces at an interval on the same steel bar, immerse the aluminum pieces in a formation solution, and perform anodic oxidation to promote the formation of an aluminum oxide medium layer film.

3. The preparation method according to claim 1, characterized in that, The polymer monomer solution further comprises poly(benzodifuran dione), and the total concentration of the poly(benzodifuran dione) in the polymer monomer solution is 0.5-5 mg / ml.

4. The production method according to claim 3, characterized by, The polymer monomer solution further comprises a binder, and the binder comprises at least one of epoxy resin and acrylic resin, and the concentration of the binder in the polymer monomer solution is 0.5-2 mg / ml.

5. The preparation method according to claim 2, wherein the concentration of component F in the surface modifier solution is 0.2-10 mg / ml; the concentration of component A in the polymerized monomer solution is 10-25 mg / ml; the concentration of component C in the outer film layer solution is 5-15 mg / ml, and the total concentration of component D is 0.2-5 mg / ml; the total concentration of component D in the oxidizing agent solution is 10-50 mg / ml. the formation solution is an aqueous solution of phosphoric acid with a concentration of 0.2-2 mg / ml and ammonium dihydrogen phosphate with a concentration of 1-10 mg / ml; 6. The production method according to claim 5, wherein the number of laminated sheets of the capacitor monolithic is 2-12 sheets. the drying method is one of vacuum drying and heat annealing drying; 7. The preparation method according to claim 6, characterized in that, the drying temperature is 60-150 °C, and the drying time is 5-30 minutes. The preparation method is prepared according to any one of claims 1-7.

8. A multilayer chip capacitor based on an n-type conductive polymer, characterized in that, ​

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