WO2013166928A1

WO2013166928A1 - Solid electrolytic capacitor carbon rubber layer and method for manufacturing same

Info

Publication number: WO2013166928A1
Application number: PCT/CN2013/074991
Authority: WO
Inventors: 丁兆龙; 王振中
Original assignee: 常州第六元素材料科技股份有限公司
Priority date: 2012-05-11
Filing date: 2013-04-28
Publication date: 2013-11-14
Also published as: CN102683038A; CN102683038B

Abstract

A method for manufacturing a solid electrolytic capacitor carbon rubber layer is related, comprising: immersing an electrode needing coating a carbon rubber layer into an emulsion containing a conductive non-metal, a binder and an organic solvent, and curing to obtain the carbon rubber layer, wherein the conductive non-metal is a graphene material. According to the solid electrolytic capacitor electrode carbon rubber layer manufactured by adopting the method, the binding force of the carbon rubber layer and a silver paste layer is improved, the content of carbon in the solid electrolytic capacitor electrode carbon rubber layer is reduced but the conduction property of the material is not reduced, the contact resistance is reduced, and the heat resistance is improved, so the solid electrolytic capacitor carbon rubber layer is suitable for massive popularization and application.

Description

Solid electrolytic capacitor carbon glue layer and preparation method thereof

Technical field

The invention relates to a carbon electrolyte layer of a solid electrolytic capacitor and a preparation method thereof, in particular to a carbon electrolyte layer of a solid electrolytic capacitor based on a graphene-derived material, and a preparation method thereof, in particular to a graphene-derived material as a conductive non-metal The solid electrolyte capacitor electrode carbon layer and the preparation method thereof belong to the technical field of solid electrolytic capacitors.

Background technique

Capacitance, also known as capacitance, refers to the amount of charge stored at a given potential difference, which is the physical quantity that characterizes the charge capacity of a capacitor. The amount of potential required to increase the potential difference between the two plates of the capacitor by one volt is the capacitance of the capacitor. Physically, a capacitor is a static charge storage medium, like a bucket that can only hold a charge, provided that there is no discharge loop and that the self-discharge effect of the dielectric leakage is removed.

The basic function of capacitors is charging and discharging. Many of the circuit phenomena extended by this basic charging and discharging function make capacitors have different uses. For example, in electric motors, we use them to generate phase shifts. It is used to generate high-energy transient discharges; in the circuit, capacitors are used to block DC, connect AC, and prevent low-frequency characteristics for coupling, DC blocking, bypassing, filtering, tuning, energy conversion, and automatic control.

Capacitors can be divided into three categories: inorganic dielectric capacitors, organic dielectric capacitors and electrolytic capacitors. The electrolytic capacitor is usually made of a metal foil (aluminum/bismuth) as a positive electrode, and an insulating oxide layer of aluminum foil (alumina/niobium pentoxide) as a dielectric. Electrolytic capacitors are classified into tantalum electrolytic capacitors and aluminum electrolytic capacitors by their positive electrodes. The negative electrode of the tantalum electrolytic capacitor usually uses manganese dioxide; and the negative electrode of the aluminum electrolytic capacitor is made of a thin paper/film or electrolyte that is immersed in the electrolyte liquid (liquid electrolyte). Composition.

The solid electrolytic capacitor is an electrolytic capacitor using a conductive polymer as a dielectric material. The conductive polymer material does not act on the alumina, and does not explode after being energized; at the same time, the solid electrolytic capacitor is a solid product, and there is no crack due to thermal expansion.

As shown in FIG. 1, a common solid electrolytic capacitor includes an anode portion 3 and a cathode portion 1. The center of the cathode portion 1 is a porous aluminum metal foil 4, and the outer portion of the porous aluminum metal foil 4 is an alumina dielectric layer. 5. The conductive polymer layer 6, the carbon glue layer 7, and the silver glue layer 8. The role of the carbon glue layer: on the one hand, preventing the silver glue layer from directly contacting the polymer, causing the silver migration to increase the leakage current; on the other hand, as a transition layer, reducing the contact resistance between the silver glue layer and the polymer, and also preventing the silver from being The oxide in the conductive polymer layer is oxidized. The carbon glue layer used in the prior art generally uses a mixture of graphite and carbon as the conductive non-metal. The defects of the above technology are as follows: On the one hand, due to the complicated surface structure of the carbon material and the large interface resistance, the capacity is greatly reduced at the rate of charge and discharge; in addition, the carbon of the general process is loose in texture and in the polymer layer. The surface distribution is loose, thereby affecting the thickness of the electrode sheet of the solid electrolytic capacitor. Therefore, minimizing the carbon content in the carbon glue layer without reducing the conductivity of the material is an urgent problem to be solved in the preparation of the electrode carbon layer of the solid electrolytic capacitor.

Summary of the invention

In view of the prior art, the carbon electrolyte layer of the solid electrolytic capacitor has a high carbon content, a carbon rubber layer is thick, and the carbon content is lowered, and the carbon rubber layer has poor conductivity. The present invention utilizes graphene excellent electrical conductivity and huge The specific surface area is selected from graphene to replace the mixture of graphite and carbon in the prior art.

Graphene is a layer of carbon atoms with a single atomic thickness. It is a single layer of carbon honeycombs formed by sp ² hybridized carbon atoms and arranged in a hexagonal plane of a single layer of atoms to form a honeycomb lattice (Honeycomb Crystal Lattice). Dimensional crystal. The invention selects graphene which has extremely excellent electrical conductivity and large specific surface area to replace the mixture of graphite and carbon, and is used as the conductive non-gold of the carbon layer of the electrode of the solid electrolytic capacitor. Genus.

One of the objects of the present invention is to provide a method for preparing a carbon electrolyte layer of a solid electrolytic capacitor. The method comprises: immersing an electrode to be coated with a carbon glue layer in an emulsion containing a conductive non-metal, a binder and an organic solvent, and curing to obtain a carbon glue layer; the conductive non-metal is a graphene material; The non-metal is a graphene-based material.

The method for preparing a silica gel layer of a solid electrolytic capacitor according to the present invention is to apply an emulsion containing a graphene material, a binder and an organic solvent to an electrode to be coated with a carbon glue layer by an impregnation method, and then apply the same to The organic solvent in the emulsion on the electrode is removed and solidified to obtain a carbon glue layer applied to the electrode.

The graphene material has excellent electrical conductivity, and the present invention adds graphene to the carbon rubber layer to ensure good electrical conductivity even in the case of a low carbon content. The large specific surface area of the graphene material allows the binder to penetrate deep into the interior, which in turn enables a stronger bond to the silver paste layer. Compared with the mixture of graphite and carbon, graphene is used as the conductive non-metal, which can reduce the carbon content while obtaining the same conductivity, and can increase the bonding force between the carbon glue layer and the silver glue layer.

The graphene-based material of the present invention is selected from graphene or graphene-derived materials.

Thus, graphene-based materials which can be known to those skilled in the art can be used in the present invention, especially graphene materials or graphene-derived materials having a large specific surface area and good electrical conductivity. The so-called graphene-derived material refers to a derivative material obtained by introducing a group onto a graphene material, for example, a derivative material obtained by hydrogenating or adding a fluorine-containing reaction, or a derivative material obtained by combining graphene with a polymer. Graphene is excellent in capacitance performance by a composite material formed with some noble metal nanoparticles or an organic conductive polymer material. There have been many reports on the acquisition of graphene-derived materials, which are available to those skilled in the art and will not be described herein.

Preferably, the graphene-based material of the present invention has a three-dimensional structure and the surface contains a large number of nano-scale micropores. Further, a graphene-based material having a conductivity of 100 mS/m, for example, an electric conductivity of 105 mS/m Graphene-based materials, 112 mS/m graphene-based materials, and 134 mS/m graphene-based materials, or graphene-based materials having micropores having a pore diameter in the range of 2 nm to 100 nm, such as graphene-based materials. The surface micropore diameters are 2-4 nm, 3-7 nm, 4.5-8.8 nm, and 7-10 nm, etc., and are more suitable for the present invention.

A method known to those skilled in the art for preparing a graphene material or a graphene-derived material having a large number of nano-scale micropores on the surface can be used to carry out the invention, and a typical but non-limiting example is microwave expansion treatment of graphene oxide, The use of a strong reducing agent such as hydrazine hydrate to reduce graphene oxide, electrochemical reduction of graphene oxide, high temperature heat treatment of graphene oxide, and the like. The method for preparing a graphene material or a graphene-derived material having a large number of micron-sized pores on the surface can be obtained by those skilled in the art based on the professional knowledge and relevant materials.

A method capable of producing a graphene-derived material having a conductivity of 100 mS/m and/or a large number of micropores having a pore diameter ranging from 2 nm to 100 nm on the surface is particularly preferably used in the present invention. For example, CN 102070140 A discloses a method of preparing a high specific surface area graphene material.

CN 102070140 A discloses a method for obtaining a high specific surface area graphene material by treatment with a strong alkali, which utilizes a reaction of a strong base and carbon at a high temperature, heat treatment or microwave irradiation to obtain a graphene powder for further chemical treatment, thereby rapidly Large quantities of micropores are etched on the surface of graphene to greatly increase the specific surface area, and high temperature treatment can further reduce graphene, thereby ensuring high conductivity of the obtained material. The graphene material prepared by the method disclosed in CN 102070140 A has not only a three-dimensional, porous structure, but also a specific surface area of up to 1500 m ² /g to 3000 m ² /g, and the obtained graphene material also has high conductivity.

Preferably, the preparation process of the graphene material having a three-dimensional structure in which the surface contains a large number of nano-scale micropores is: reacting the graphene powder obtained by heat treatment or microwave irradiation with a strong base, and preparing by post-treatment. Specifically, the step of preparing a graphene material having a three-dimensional structure containing a plurality of nano-scale micropores includes: (1) placing the graphite oxide in water and performing ultrasonic treatment to obtain a graphite oxide suspension; (2) configuring a strong alkali aqueous solution; (3) adding the strong alkali aqueous solution of the step (2) to the graphite oxide suspension of the step (1), stirring, filtering, and drying; (4) sintering the solid obtained after the step (3) is dried; (5) The solid obtained in the step (4) is washed with water, filtered, and dried.

Preferably, in the method for preparing the graphene, the ultrasonic time in the step (1) is l-5h, for example, lh, 1.2h, 2h, 2.4h, 3.5h, 4.1h, 4.9h, and 5h, etc., preferably 2-3 h, further preferably 2.5 h. Preferably, the concentration of the graphite oxide in the step (1) in water is 0.01-10 mg/mL, for example, 0.01 mg/mL, 0.04 mg/mL, 0.13 mg/mL, 0.94 mg/mL, 1.6 mg/mL, 2.34 mg. /mL, 3.67 mg/mL, 4.89 mg/mL, 5.2 mg/mL, 7.1 mg/mL, 9.42 mg/mL, and 10 mg/mL, etc., preferably 2-5 mg/mL, and more preferably 4 mg/mL. Preferably, the concentration of the strong base in the step (2) is 0.2-20 mol/L, for example, 0.2 mol/L, 0.4 mol/L, 3.1 mol/L, 7.6 mol/L, 9.9 mol/L, and 16.1 mol/L. 18.7 mol/L, 20 mol/L, etc., preferably 3-15 mol/L, further preferably 10 mol/L. Preferably, in the step (2), the mass ratio of the strong base to the graphite oxide is (1-50):1, for example, 1:1, 5:1, 13:1, 21:1, 39:1, 44:1 And 50:1, etc., preferably (5-33): 1. Preferably, the sintering temperature of the step (4) is 700-1200 ° C, such as 700 ° C, 705 ° C, 760 ° C, 920 ° C, 1060 ° C, 1137 ° C, 1190 ° C and 1200 ° C or the like, preferably 750-1180 °C.

It should be apparent to those skilled in the art that the preparation method of the graphene material having a large number of nano-scale micropores and/or a three-dimensional structure on the surface of the present invention is not limited to the method described above, and any graphene capable of preparing a composite requirement can be prepared. Both can be used in the present invention.

The role of the binder in the present invention is to ensure a firm bond between the graphene particles, stabilize the carbon glue layer, and ensure that the carbon glue layer and the silver glue layer can be firmly combined. Adhesives having a bonding function which can be obtained by those skilled in the art can be used in the present invention. Preferably, the binder of the present invention is a resin binder. Preferably, the resin-based binder of the present invention is preferably one or a combination of at least two of an epoxy resin, an acrylic resin, a polymethyl methacrylate, and a urethane resin, such as an epoxy resin/acrylic resin. , epoxy resin / polymethacrylic resin, acrylic resin / polymethacrylic resin / polyurethane resin. The epoxy resin has the advantages of strong mechanical properties, strong adhesion, small cure shrinkage, good stability, good heat resistance, and the like, and therefore an epoxy resin is preferred in the present invention.

In the present invention, the function of the organic solvent is to uniformly disperse the conductive non-metal material and the binder, and to ensure uniform thickness of the carbon rubber layer when coating the electrode sheets to be coated. After the electrode is coated with the carbon layer, the organic solvent should be removed to facilitate curing of the carbon layer. Therefore, an organic solvent which can be effectively dispersed by a person skilled in the art and which can be effectively removed after the coating is completed can be used in the present invention.

Preferably, the organic solvent of the present invention is hydrazine, hydrazine-dimethylformamide, 1-methyl-2-pyrrolidone, dimethyl sulfoxide, tetrahydrofuran, propylene carbonate, acetone, acetonitrile, pyridine and chlorine. One or a combination of at least two of benzene, such as hydrazine, hydrazine-dimethylformamide/acetonitrile, acetone/acetonitrile, pyridine/chlorobenzene, dimethyl sulfoxide/tetrahydrofuran, propylene carbonate/acetone / Acetonitrile and so on. Ν, Ν-dimethylformamide is called "universal solvent" and has good solubility for various polymers such as polyethylene, polyvinyl chloride, polyacrylonitrile, polyamide, and the like. 1-Methyl-2-pyrrolidone is also very soluble in polymers and is often used as a solvent for dissolving polymers and as a medium for polymerization. The organic solvent of the present invention is preferably hydrazine, hydrazine-dimethylformamide and/or 1-methyl-2-pyrrolidone.

As a preferred technical solution, the method of the present invention comprises the following steps:

(1) mixing a graphene material, a resin binder, and an organic solvent to form an emulsion;

(2) the electrode to be coated with the carbon glue layer is covered with the carbon glue layer emulsion by dipping in the cathode layer preparation emulsion;

(3) Drying and curing, preparing a carbon glue layer. In the mixed emulsion, the content of the graphene material, the resin binder and the organic solvent is related to the stability, the binding force, the conductivity, the carbon content and the preparation time of the carbon rubber layer, such as graphene. The more the material, the more carbon content of the carbon layer increases, and the conductivity increases; and the type and amount of the resin binder have a great relationship with the stability of the carbon layer and the adhesion to the silver layer; The solvent is related to the uniformity and stability of the dispersion of the graphene material and the resin binder, thereby affecting the distribution uniformity and bonding force of the graphene of the carbon binder layer.

Preferably, the graphene material in the step (1) accounts for 0.1-20% by weight of the mixed emulsion, for example, 0.1 wt%, 0.13 wt%, 0.87 wt%, 1.69 wt%, 7.5 wt%, 14 wt%, 16.3 wt%. %, 18.4 wt%, 19.8 wt%, 20 wt%, etc., preferably 0.1 to 10% by weight, further preferably 3 to 10% by weight.

Step (1) The resin-based binder accounts for 25 to 35 wt% of the mixed emulsion, for example, 25 wt%, 26 wt%, 34 wt P 35 wt%, etc., preferably 30 wt%.

The organic solvent in the step (1) accounts for 55-74% by weight of the mixed emulsion, for example, 55 wt%, 57 wt%, 61 wt%, 66 wt%, 73% [% and 74 wt%, etc., preferably 60-65 wt%.

Preferably, the mixing of the step (1) is carried out without any special requirements, and any one of the mixing methods known to those skilled in the art can realize the present invention. Typical but non-limiting examples are stirring, shaking, ultrasonic, and the like. The optional technical solution of the step (1) of the present invention is: after stirring and mixing the graphene material, the resin binder and the organic solvent, ultrasonically obtaining a black dispersion which is uniformly dispersed.

Preferably, in the step (3) of the present invention, the drying and curing are carried out in an oven, preferably pre-baking, and then increasing the temperature to continue drying. In order to prevent the graphene from being completely or partially oxidized to graphene oxide during drying and solidification to affect its conductivity, the oven is preferably a vacuum drying oven.

Preferably, the pre-baking temperature of the step (3) of the present invention is 60-95 ° C, for example, 60 ° C, 63 ° C, 71 ° C, 77 ° C, 86 ° C, 92 ° C, 95 ° C. The pre-bake time is 8-20 min, such as 8 min, 9 min, 15 min, 17 min, 19 min, 20 min, and the like. Preferably, the drying temperature is 100-200 ° C, for example Such as 100 ° C, 103 ° C, 125 ° C, 136 ° C, 158 ° C, 179 ° C, 182 ° C, 198 ° C, 200 ° C, etc.; the drying time is 30-120 min, such as 30 min 35 min, 78 min, 106 min, 118 min, 120 min, etc.; further preferably, the drying temperature is 150-180 ° C, and the drying time is 30-60 min.

A second object of the present invention is to provide a carbon electrolyte layer of a solid electrolytic capacitor, which is prepared by the method of the present invention, wherein the carbon adhesive layer has a density of 0.05 g/cm ³ to lg/cm ³ . The thickness is 50ηηι-500 ηι, such as 50nm, 52nm, 60nm, 122nm, 134nm, 158nm, 250nm, 332nm, 430nm, 487nm, 788nm, 1μηι, 34μηι, 123μηι, 289μηι, 444μηι, 498μηι, 500μηι, etc.; carbon content is 0.1- 20 wt%, such as 0.1 wt%, 0.5 wt%, 2 wt%, 4.4 wt%, 7 wt%, 8.9 wt%, 12.2 wt%, 17 wt%, 18.1 wt%, 19.9 wt%, 20 wt%, and the like.

A third object of the present invention is to provide a solid electrolytic capacitor.

In theory, a perfect capacitor does not generate any energy loss by itself, but in reality, because the material used to make the capacitor has resistance, the dielectric of the capacitor is depleted, and the capacitor becomes not perfect for various reasons. This loss is external and appears as a resistor in series with the capacitor, so it is called "equivalent series resistance", the English name is Equivalent Series Resistance, abbreviated as ESR.

Therefore, it can be known that the ESR of the capacitor has a great relationship with the material of the capacitor. The solid electrolytic capacitor provided by the present invention contains the carbon adhesive layer of the present invention, and has an ESR of 5-20 ηιΩ, for example, 5 ηιΩ, 9ηιΩ, 13ηιΩ, 18ηιΩ. , 20ηιΩ, etc.

The preparation method of the solid electrolytic capacitor of the present invention is: immersing the product covered with the graphene carbon rubber layer into the silver paddle by the dipping method, drying and solidifying after the dipping, to obtain a monolithic solid electrolytic capacitor.

Preferably, the drying and curing temperature is 120-180 ° C, such as 120 ° C, 131 ° C, 144 ° C, 153 ° C, 160 ° C, 175 ° C, 179 ° C, 180 ° C, etc. Preferably, the drying curing time is 30-120 min, for example 30 min, 45 min. 78 min. 95 min. 118 min. 120 min. Etc., preferably 30-60 min.

As a preferred technical solution, the method for preparing the solid electrolytic capacitor of the present invention is as follows: the product covered with the graphene carbon rubber layer is dipped into the silver paste by the dipping method, and after being immersed, it is baked in an oven at 150 ° C for 30-60 minutes, A monolithic solid electrolytic capacitor was produced.

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

(1) The carbon electrolyte layer of the solid electrolytic capacitor prepared by the present invention uses graphene instead of the carbon and graphite of the prior art, and can reduce the carbon content under the premise of satisfying the conductivity, thereby reducing the thickness of the electrode sheet. The carbon rubber layer provided by the invention has strong bonding force, in particular, improves the bonding force between the carbon rubber layer and the silver paste layer, reduces the carbon content in the carbon electrolyte layer of the solid electrolytic capacitor, but does not reduce the conductive property of the material, and reduces the contact. Resistance, increased heat resistance, suitable for large-scale promotion.

(2) As a preferred technical solution, the present invention uses the preparation of the porous, three-dimensional structure of the graphene material disclosed in CN 102070140 A to replace the carbon and graphite in the carbon glue layer in the prior art, and can improve the first cathode layer and the silver paste. The bonding force of the layer reduces the carbon content of the first cathode layer in the electrode of the solid electrolytic capacitor without reducing the electrical conductivity of the material, reducing the contact resistance, and increasing the heat resistance.

(3) The preparation method of the carbon rubber layer provided by the invention is simple, easy to operate, and suitable for mass production. And as a preferred technical solution, the method for preparing a porous, three-dimensional structure graphene material provided by the present invention is also very simple, and is suitable for industrial large-scale production, so the present invention has a very broad market forefront.

(4) The electrode sheet of the solid electrolytic capacitor provided by the present invention has a small thickness under the premise of the same conductivity, and can provide a larger use space in application, and has a broad application prospect.

DRAWINGS

1 is a schematic structural view of a solid electrolytic capacitor.

2 is a schematic view showing the microstructure of a carbon electrolyte layer of a solid electrolytic capacitor according to the present invention. Figure 3 is a laminated solid electrolytic capacitor of the present invention.

Wherein, 1-cathode portion; 2-insulating layer; 3-anode portion; 4-porous aluminum metal foil; 5-alumina dielectric layer; 6-conductive polymer layer; 7-carbon adhesive layer; Layer; 9- Partial enlarged view of the carbon rubber layer of the present invention; 10-monolithic solid electrolytic capacitor.

detailed description

In order to facilitate the understanding of the present invention, the present invention is exemplified by the following. It should be understood by those skilled in the art that the present invention is not to be construed as limited.

Example 1

A method for preparing a carbon electrolyte layer of a solid electrolytic capacitor, comprising the following preparation steps:

(1) Weighing a certain amount of graphene-derived material powder produced by the method described in the patent CN102070140A, placed in an agate mortar, and grinding uniformly; the ground powder, organic solvent Ν, Ν-dimethylformamide (DMF) And the binder epoxy resin according to the parts by mass: graphene 5%; binder 30%; organic solvent 65% mixing and stirring, ultrasonic for 30 minutes, to obtain a uniform dispersion of black suspension;

(2) covering the graphene carbon layer with an electrode coated with a carbon glue layer in a graphene suspension by dipping;

(3) pre-baking in an oven at 80 ° C for 10 min, and baking in an oven at 150 ° C for 30-60 min;

(4) Test the resistivity of the carbon layer: Apply a 10mmX 40mm X 25m carbon film on the glass slide, pre-bake for 10 minutes in an oven at 80 ° C, and then cure in an oven at 150 ° C for 30-60 min. Test the resistance of 40mm length direction;

(5) Preparation of a solid electrolytic capacitor: The product covered with the graphene carbon rubber layer is immersed in a silver paste by dipping, and after being immersed, it is baked in an oven at 150 ° C for 30-60 min to obtain a monolithic solid electrolytic capacitor. The monolithic solid electrolytic capacitor was assembled several times to prepare a laminated solid electrolytic capacitor.

Example 2 A method for preparing a carbon electrolyte layer of a solid electrolytic capacitor, comprising the following preparation steps:

(1) Weighing a certain amount of graphene-derived material powder produced by the method described in the patent CN102070140A, placed in an agate mortar, and grinding uniformly; the ground powder, the organic solvent 1-methyl-2-pyrrolidone and The binder polymethyl methacrylate according to the parts by mass: graphene 10%; binder 30%; organic solvent 60% mixed and stirred, ultrasonic for 30 minutes, to obtain a uniform dispersion of black suspension;

(5) Preparation of a solid electrolytic capacitor: The product covered with the graphene carbon rubber layer is immersed in a silver paste by dipping, and after being immersed, it is baked in an oven at 150 ° C for 30-60 min to obtain a monolithic solid electrolytic capacitor. The monolithic solid electrolytic capacitor is further assembled by multiple times to prepare a laminated solid electrolytic capacitor.

Example 3

(1) Weigh a certain amount of graphene material powder, placed in an agate mortar, and grind evenly; the ground powder, organic solvent dimethyl sulfoxide and binder acrylic resin in parts by mass: graphene 0.1% ; binder 35%; organic solvent 64.9% mixed and stirred, ultrasonic for 30 minutes, to obtain a uniform dispersion of black suspension;

(3) pre-baking in an oven at 60 ° C for 15 min, and baking in a 200 ° C oven for lOOmin; (4) Test the resistivity of the carbon layer: Apply a 10mm×40mm X 25m carbon film on the glass slide, pre-bake in an oven at 80°C for 10min, and then cure in an oven at 150°C for 30-60min. Test the resistance of 40mm length direction;

Preparation of solid electrolytic capacitors:

(4) The product covered with the graphene carbon rubber layer was immersed in the silver paste by the dipping method, and after the immersion was completed, it was baked in an oven at 180 ° C for 30 minutes to obtain a monolithic solid electrolytic capacitor.

Example 4

A method of preparing a solid electrolytic capacitor, comprising the steps of:

First, preparing a three-dimensional graphene material having a large number of nano-scale micropores on the surface includes the following steps: (1) placing the graphite oxide in water (the concentration of graphite oxide is 4 mg/mL), performing ultrasonic treatment, ultrasonic power 200 W, ultrasonic time 2.5h, obtaining a graphite oxide suspension; (2) arranging a 7 mol/L sodium hydroxide aqueous solution; (3) adding the sodium hydroxide aqueous solution of the step (2) to the graphite oxide suspension of the step (1) (guarantee hydrogen The mass ratio of sodium oxide to graphite oxide is 40:1), stirred, filtered, and dried; (4) the solid obtained by drying step (3) is sintered at 1000 ° C; (5) step (4) is obtained. The solid is washed with water, filtered, and dried to obtain a three-dimensional graphene material having a large number of nano-scale micropores on its surface.

A method of preparing a carbon electrolyte layer of a solid electrolytic capacitor, comprising the following preparation steps:

(1) Weighing a certain amount of three-dimensional graphene material graphene material powder containing a large number of nano-scale micropores on the surface, placed in an agate mortar, and grinding uniformly; the ground powder, organic solvent dimethyl sulfoxide and sticky Coating agent acrylic resin and epoxy resin (mass ratio 20:3) according to the mass fraction: graphene 20%; binder 25%; organic solvent 55% mixing and stirring for 40 minutes, to obtain a uniform dispersion of black suspension Liquid

(3) pre-baking in an oven at 95 ° C for 8 min, and curing in an oven at 100 ° C for 120 min;

(4) Test the resistivity of the carbon layer: Apply a 10mm×40mm×25m carbon film on the glass slide, pre-bake in an oven at 95°C for 8min, then cure in a 100°C oven for 120min, and test the length of 40mm. Resistance

(5) Preparation of solid electrolytic capacitor: The product covered with the graphene carbon rubber layer is immersed in the silver paste by dipping method, and after being immersed, it is baked in an oven at 120 ° C for 50 minutes to obtain a monolithic solid electrolytic capacitor, and the single piece is obtained. The solid electrolytic capacitor is further assembled by a plurality of times to prepare a laminated solid electrolytic capacitor.

Example 5

A method of preparing a solid electrolytic capacitor, comprising the steps of:

First, preparing a three-dimensional graphene material having a large number of nano-scale micropores on the surface includes the following steps: (1) placing the graphite oxide in water (the concentration of graphite oxide is 10 mg/mL), performing ultrasonic treatment, ultrasonic power 500 W, ultrasonic time 5h, obtaining a graphite oxide suspension; (2) disposing a 10 mol/L sodium hydroxide aqueous solution; (3) adding the sodium hydroxide aqueous solution of the step (2) to the graphite oxide suspension of the step (1) (guaranteeing the hydroxide The mass ratio of sodium to graphite oxide is 30:1), stirred, filtered, and dried; (4) The solid obtained by drying step (3) is sintered at 1200 ° C; (5) obtained by step (4) The solid is washed with water, filtered, and dried to obtain a three-dimensional graphene material having a large number of nano-scale micropores on its surface.

(1) Weigh a certain amount of graphene material powder, placed in an agate mortar, and grind evenly; the ground powder, organic solvent acetonitrile and acetone (volume ratio 1:1) and binder polyurethane resin according to the mass fraction: Graphene 1%; binder 25%; organic solvent 74% mixed and stirred for 20 minutes, to obtain dispersion Uniform black suspension;

(3) pre-baking in an oven at 95 ° C for 18 min, and baking in an oven at 200 ° C for 30 min;

(4) Test the resistivity of the carbon layer: Apply 10mmX40mmX25m carbon film on the glass slide, pre-baking in a 95°C oven for 18min, then cure in a 200°C oven for 30min, test 40mm length direction. Resistance

(5) Preparation of solid electrolytic capacitor: The product covered with the graphene carbon rubber layer was immersed in the silver paste by dipping method, and after being immersed, it was baked in an oven at 150 ° C for 62 minutes to obtain a monolithic solid electrolytic capacitor, which was monolithic. The solid electrolytic capacitor is further assembled by a plurality of times to prepare a laminated solid electrolytic capacitor.

Comparative example

(1) Weigh a certain amount of toner, place it in an agate mortar, and grind it evenly; place the ground powder, organic solvent Ν, Ν-dimethylformamide and binder epoxy resin according to the mass fraction: toner 5%; binder 30%; organic solvent 65% mixed and stirred uniformly to obtain a black suspension;

(2) the electrode to be coated with the carbon glue layer is covered with a carbon glue layer by dipping in the suspension obtained in the step (1);

(3) pre-bake in an oven at 80 ° C for 10 min, and bake in an oven at 150 ° C for 30-60 min;

(4) Test the resistivity of the carbon layer: Apply 10mmX40mmX25m carbon film on the glass slide, pre-bake lOmin in 80°C oven, then cure in 150°C oven for 30-60min, test 40mm length Directional resistance

(5) Preparation of solid electrolytic capacitor: The product covered with the graphene carbon rubber layer is immersed in the silver paste by dipping method, and after being immersed, it is baked in an oven at 150 ° C for 30-60 min to obtain a monolithic solid electrolytic capacitor. The monolithic solid electrolytic capacitor was assembled again by multiple times to prepare a laminated solid electrolytic capacitor. Comparative Test

The carbon content thickness and electric resistance of the carbon electrolyte layer of the solid electrolytic capacitor obtained in Example 1 and Example 5 and the comparative example were tested; and the equivalent series resistance (ESR) of the solid electrolytic capacitor was examined. The performance test results are shown in Table 1. Show.

Table 1 Comparison of performance of carbon electrolyte layer of solid electrolytic capacitor and prepared solid electrolytic capacitor

It can be seen from the comparison test that the solid electrolytic capacitor using the graphene as the carbon adhesive layer provided by the present invention has a smaller carbon powder layer and a smaller electric resistance than the ordinary solid electrolytic capacitor. The ESR of the obtained solid electrolytic capacitor is also much smaller than that of the ordinary solid electrolytic capacitor, and can reach a minimum of 5 m Ω. In particular, a three-dimensional graphene material having a large number of nano-scale micropores on its surface is used as a carbon adhesive layer, and the thickness is only 36 μ ηι under a carbon content of 20 wt%, and the electric resistance is only 10 Ω. The prepared ESD has a very small ESR of only 5ηι Ω, which is unmatched by the prior art and has a very broad use and market prospect. The Applicant stated that the above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, it is still possible for those skilled in the art to The technical solutions described in the foregoing embodiments are modified, or the technical features are equivalently replaced. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

claims

1. A method for preparing a carbon glue layer of a solid electrolytic capacitor, characterized in that the method is to immerse the electrode to be coated with a carbon glue layer into an emulsion containing conductive non-metals, resin binders and organic solvents. Coating and curing to obtain a carbon glue layer; in the total mass of the emulsion, conductive non-metals account for 0.1-20wt%; resin binders account for 25-35wt% _; organic solvents account for 55-74wt%.

2. The method of claim 1, wherein the conductive non-metal is a graphene-based material; the graphene-based material has a three-dimensional structure and contains nanoscale micropores on its surface, and its pore diameter is in the range of 2nm-100nm. Within; The electrical conductivity of the graphene-based material is 100mS/m.

3. The method according to claim 1 or 2, characterized in that the resin binder is one or more of epoxy resin, acrylic resin, polymethyl methacrylate, and polyurethane resin; The organic solvent is one of N, N-dimethylformamide, 1-methyl-2-pyrrolidinone, dimethyl sulfoxide, tetrahydrofuran, propylene carbonate, acetone, acetonitrile, pyridine, and chlorobenzene , or several types.

4. The method according to any one of claims 1 to 3, characterized in that the method includes the following steps:

①Mix conductive non-metals, resin binders and organic solvents evenly to form an emulsion; of the total mass of the emulsion, conductive non-metals account for 0.1-20wt% _; resin binders account for 25-35wt% _; organic solvents account for 55-74 wt%;

② Dip the electrode that needs to be coated with the carbon glue layer into the emulsion prepared in step ① for dip coating, so that the emulsion covers the electrode surface;

③ Pre-dry, raise the temperature and then dry the electrode obtained in step ② before solidifying, and prepare a carbon glue layer on the electrode surface; the pre-drying temperature is 60-95°C, and the pre-drying time is 8- 20min _; the temperature for heating and drying is 100-200°C, and the time for heating and drying is 30-120min.

5. The method according to claim 4, characterized in that, the conductive non-metal in step ① is graphene material; the resin binder is epoxy resin, acrylic resin, polymethyl methacrylate, One or more of the polyurethane resins; the organic solvent is N, N-dimethylformamide, 1-methyl - One or more of 2-pyrrolidinone, dimethyl sulfoxide, tetrahydrofuran, propylene carbonate, acetone, acetonitrile, pyridine, and chlorobenzene.

6. The method of claim 5, wherein the graphene-based material is prepared by reacting graphene powder obtained by heat treatment or microwave irradiation with a strong alkali and post-processing; the graphene-based material The material has a three-dimensional structure and contains nano-scale micropores on the surface, and its pore diameter is in the range of 2nm-100nm; the electrical conductivity of graphene-based materials is 1001118/111.

7. The method of claim 4, wherein the temperature for heating and drying in step ③ is 150-180°C, and the time for heating and drying is 30-60 minutes.

8. The method according to claim 4 or 7, characterized in that the pre-drying and heating and re-drying in step ③ are completed in an oven.

9. The method according to claim 8, characterized in that the pre-drying and heating and re-drying are completed in a vacuum drying oven.

10. The method according to any one of claims 1 to 9, characterized in that the density of the carbon glue layer produced by the method is 0.05g/ ^cm3 to 1g/ ^cm3 , the thickness is 50nm-500μm, and the carbon content is The resistance is 0.1-20wt%, and the resistance is 10-150 Ω.