Production process of high-adhesion solid-state capacitor carbon foil

Abstract

The invention discloses a high-adhesion solid-state capacitor carbon foil production process, and relates to the technical field of solid-state capacitor carbon foils. The preparation method comprises the following steps: generating a three-dimensional graphene layer in situ on the surface of an aluminum foil by a chemical vapor reduction method; secondly, the graphene layer is modified by utilizing aluminum nitrate ammonium nitrate, and then the Ni-Al layer with a continuous lamellar structure is prepared on the graphene layer through electrochemical deposition, so that active sites are provided, and the ion diffusion capability of the carbon foil is remarkably improved; finally, mixing ethylene diamine tetraacetic acid dipotassium salt and corn starch to prepare nitrogen-doped carbon aerogel, preparing the nitrogen-doped carbon aerogel into powder, and coating the surface of the Ni-Al layer with the powder to prepare a four-layer composite carbon foil; by doping nitrogen atoms, the surface chemical performance of the carbon aerogel material can be changed, the wettability of an electrode is improved, the diffusion rate of electrolyte ions is increased, and the specific capacity of the material is increased, so that the overall electrochemical performance of the carbon foil is improved. The four-layer composite carbon foil prepared by the invention has the effects of high adhesion and excellent electrochemical performance.

Description

Technical Field

[0001] The present invention relates to the technical field of solid capacitor carbon foils, specifically to a production process of high-adhesion solid capacitor carbon foils. Background Art

[0002] Solid capacitors, also known as solid aluminum electrolytic capacitors, have the biggest difference from ordinary liquid aluminum electrolytic capacitors in that different dielectric materials are adopted. The dielectric material of liquid aluminum capacitors is electrolyte, while the dielectric material of solid capacitors is conductive polymer, which will not react with aluminum oxide and will not explode after being energized. They are widely used due to their low ESR and high rated ripple current. The cathode foil of solid capacitors is made by attaching conductive paste to the surface of etched aluminum foil. Therefore, the uniformity, stability and continuity of the conductive paste are directly related to the surface quality of the finished carbon foil, the volume capacity of solid aluminum electrolysis, the anti-oxidation and corrosion resistance of the aluminum foil surface, etc.

[0003] At present, the structure of the negative carbon foil of solid capacitors in use is mainly composed of aluminum foil and graphite compounded on its surface. In actual use, the graphite on the surface of the aluminum foil often falls off in the negative carbon foil of solid capacitors with the above structure, affecting the service life of the capacitor. In order to prevent the graphite from falling off the surface of the aluminum foil and extend the service life of the negative carbon foil of solid capacitors, in the prior art, an adhesive is used to make the graphite into a paste and then coated on the surface of the aluminum foil. Although the capacitor with this structure can prevent the graphite from falling off the surface of the aluminum foil to a certain extent, due to the addition of the adhesive, the conductive performance and capacitance ratio of the capacitor are affected. In addition, the capacitor with the above structure does not fundamentally solve the problem of graphite falling off the surface of the aluminum foil. Summary of the Invention

[0004] The purpose of the present invention is to provide a production process of high-adhesion solid capacitor carbon foils to solve the problems existing in the prior art.

[0005] To solve the above technical problems, the present invention provides the following technical solution: A production process of high-adhesion solid capacitor carbon foils, including the following process steps:

[0006] (1) Put polymethyl methacrylate powder on the surface of aluminum foil and then put it into a tubular furnace for in-situ chemical vapor reduction; the reduction temperature is 850 - 950 °C, the reduction atmosphere is hydrogen, the protective atmosphere is argon, and the flow ratio of hydrogen to argon is 1:0.5 - 2; the reduction time is 10 - 20 min to obtain aluminum foil with three-dimensional graphene attached to its surface;

[0007] (2) Add the aluminum foil with three-dimensional graphene attached to its surface to an aqueous ammonium carbonate solution with a solid-liquid ratio of 1:5, stir at a speed of 120 rpm for 20 min, then slowly add the aluminum nitrate aqueous solution to the ammonium carbonate solution, stir at 120 rpm for 30 min and then filter. Take the filtrate and wash it twice with deionized water, and dry it in a drying oven at 50 °C to obtain the modified graphene aluminum foil; in the Ni-Al solution, electro-deposit at a constant current of 10 mA for 10 min to deposit Ni-Al on the modified graphene aluminum foil. After the deposition, wash the modified graphene aluminum foil with deposited Ni-Al three times with deionized water and alcohol, and then vacuum dry it at 80 °C for 12 h to obtain the metal graphene aluminum foil;

[0008] (3) Add 3.5 parts of diethylene glycol butyl ether, 2 parts of N,N-dimethylacetamide and 1.5 parts of terpineol to the stirring kettle in sequence, with a stirring speed of 120 rpm and a temperature of 40 °C, stir and mix for 30 min, then add 0.1 part of polyester acrylate resin and 0.3 part of epoxy acrylate resin, stir and mix for 1 h at a stirring speed of 60 rpm, then add 0.01 - 0.05 part of nano-aerogel particles, 0.01 part of antioxidant 1010, 0.02 part of aluminate coupling agent, and mix for 2 h at a stirring speed of 70 rpm to obtain the slurry; coat the slurry on the surface of the metal graphene aluminum foil to obtain the four-layer composite carbon foil.

[0009] Further, in the step (1), the thickness of the aluminum foil is 20 - 60 μm, and the thickness of the polymethyl methacrylate powder stacked on the surface of the aluminum foil is 1 - 5 μm.

[0010] Further, in the step (1), the gas flow rate is 200 - 300 ml / min.

[0011] Further, in the step (2), the impregnation method is used to modify the aluminum foil with three-dimensional graphene attached to its surface. Dissolve aluminum nitrate in deionized water to make an aluminum nitrate aqueous solution, and the mass ratio of aluminum nitrate to deionized water is 12:1 - 24; dissolve ammonium carbonate in deionized water to make an ammonium nitrate aqueous solution, and the mass ratio of ammonium nitrate to deionized water is 12:1 - 24.

[0012] Further, the preparation method of the Ni-Al solution in the step (2) is: Dissolve 2.7 mmol of Ni(NO 3 ) 2 ·6H 2 0, 0.9 - 2.7 mmol of Al(NO 3 ) 3 ·6H 2 0 to make a solution with a concentration of 80 mmol / L, add 0.8648 g of urea and dissolve it in 100 mL of deionized water, and after ultrasonic oscillation at 40 kHz for 10 min, obtain the Ni-Al solution.

[0013] Further, the degree of vacuum for vacuum drying in step (2) is 0.085 MPa.

[0014] Further, in step (3), dipotassium ethylenediaminetetraacetate and corn starch are ground into a uniform mixture according to different mass ratios of 2 - 5:1. The mixture is prepared into a mixed aqueous solution with deionized water, and then formaldehyde and resorcinol are added. Using sodium carbonate as a catalyst, it is stirred evenly at a speed of 240 rpm for 30 min, and then ultrasonicated at 40 kHz for 30 min; then the mixed solution is injected into a mold, sealed, and treated at 80 °C for 3 d to form a wet gel; the wet gel is soaked in ethanol for 3 d, and this is repeated 3 times. After supercritical drying with CO 2 supercritical drying, that is, a mixed aerogel is obtained; finally, it is carbonized at a high temperature of 600 - 800 °C for 4 h under nitrogen protection to obtain a nitrogen-doped carbon aerogel; the aerogel is crushed into particles with a particle size of 50 nm for standby.

[0015] Further, the concentration of the mixed aqueous solution is 20 g / L.

[0016] Further, the mass ratio of the mixed aqueous solution, formaldehyde, resorcinol, and sodium carbonate is: 1: 0.05: 0.0125: 0.005.

[0017] Further, when coating the slurry in step (3), the coating thickness is 20 - 30 μm, and it is left standing for 2 h; after that, the foil tape is sent into a high-temperature furnace. The heating rate of the high-temperature furnace is 10 °C / min, and it is heated to 350 °C and kept warm for 2 h. Then, it is cooled to room temperature at a cooling rate of 20 °C / min. Then, the foil is inverted to check for damage, and the damaged part is removed with a cutting machine. The foil tape is inspected and packaged for storage.

[0018] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0019] The present invention prepares a four-layer composite carbon foil. The first layer is an aluminum foil base layer, the second layer is a three-dimensional graphene layer, the third layer is a continuous layered Ni - Al layer, and the fourth layer is a nitrogen-doped carbon aerogel layer to achieve the effects of high adhesion and excellent electrochemical properties.

[0020] First, on the surface of the aluminum foil, using polymethyl methacrylate as the carbon source, through in-situ chemical vapor reduction method, the decomposed carbon atoms in-situ generate a three-dimensional graphene layer on the surface of the aluminum foil. The low-density three-dimensional graphene layer has better electrochemical performance than two-dimensional graphene, and the in-situ grown graphene has a strong binding force with the surface of the aluminum foil. Secondly, use aluminum nitrate and ammonium nitrate to modify the graphene layer, and then prepare a Ni-Al layer with a continuous sheet structure on the graphene layer through electrochemical deposition. The three-dimensional graphene and the continuous metal sheet layer provide rich redox active sites, combining the electrical conductivity of graphene and the redox characteristics of metal oxides. The synergistic effect of the two significantly improves the ion diffusion ability of the carbon foil. Finally, use dipotassium ethylenediaminetetraacetate as the nitrogen source, mix it with corn starch to prepare an aerogel, and then obtain a structurally stable nitrogen-doped carbon aerogel through high-temperature carbonization. Make it into a powder and coat it on the surface of the Ni-Al layer to prepare a four-layer composite carbon foil. Doping nitrogen atoms can change the surface chemical properties of the carbon aerogel material, improve the wettability of the electrode, and increase the diffusion rate of electrolyte ions. At the same time, nitrogen atoms can form nitrogen-containing functional groups with the carbon aerogel framework. These nitrogen-containing functional groups can make the electrode material generate pseudocapacitance, thereby increasing the specific capacitance of the material, and thus improving the overall electrochemical performance of the carbon foil. The combination of the deposition effect of the second and third layers and the coating effect of the fourth layer makes the composite carbon foil of the present invention firmly bonded to each other and not easy to fall off. Detailed implementation mode

[0021] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0022] In order to more clearly illustrate the method provided by the present invention, the following examples are used for detailed description. The test methods for each index of a high-adhesion solid-state capacitor carbon foil made in the following examples are as follows:

[0023] Service life: The samples prepared in the examples and the comparative examples are tested for life data in an air atmosphere, and the average value is taken after 3 tests.

[0024] Capacitance: Using the samples prepared in the examples and the comparative examples as the negative electrode foil, and a positive electrode aluminum foil with a formation voltage of 10V and a specific capacitance of 230 μF / cm 2 as the positive electrode foil, a solid-state capacitor is prepared to test the electrical performance.

[0025] Example 1; (1) Put polymethyl methacrylate powder on the surface of an aluminum foil with a thickness of 20 μm and then place it in a tubular furnace for in-situ chemical vapor reduction. The thickness of the polymethyl methacrylate powder stacked on the aluminum foil surface is 1 μm; the reduction temperature is 850 °C, the reduction atmosphere is hydrogen, the protective atmosphere is argon, the flow rate ratio of hydrogen to argon is 1:0.5, and the gas flow rate is 200 ml / min; the reduction time is 10 min to obtain an aluminum foil with three-dimensional graphene attached to its surface;

[0026] (2) Use the impregnation method to modify the aluminum foil with three-dimensional graphene attached to its surface. First, dissolve aluminum nitrate in deionized water to make an aluminum nitrate aqueous solution, and the mass ratio of aluminum nitrate to deionized water is 12:1. Dissolve ammonium carbonate in deionized water to make an ammonium nitrate aqueous solution, and the mass ratio of ammonium nitrate to deionized water is 12:1; then add the aluminum foil with three-dimensional graphene attached to its surface to the ammonium carbonate aqueous solution, with a solid-liquid ratio of 1:5, stir at a speed of 120 rpm for 20 min, and then slowly add the aluminum nitrate aqueous solution to the ammonium carbonate solution. After stirring at 120 rpm for 30 min, filter, take the filtrate, wash it 2 times with deionized water, and dry it in a drying oven at 50 °C to obtain a modified graphene aluminum foil; Dissolve 2.7 mmol Ni(NO 3 ) 2 ·6H 2 0, 0.9 mmol Al(NO 3 ) 3 ·6H 2 0 to prepare a solution with a concentration of 80 mmol / L, add 0.8648 g of urea and dissolve it in 100 mL of deionized water. After ultrasonic oscillation at 40 kHz for 10 min, obtain a Ni-Al solution; In the Ni-Al solution, electro-deposit at a constant current of 10 mA for 10 min to deposit Ni-Al on the modified graphene aluminum foil. After the deposition, wash the modified graphene aluminum foil with deposited Ni-Al 3 times with deionized water and alcohol, and then vacuum dry it at 80 °C for 12 h, with a vacuum degree of 0.085 MPa to obtain a metal graphene aluminum foil;

[0027] (3) Grind potassium ethylenediaminetetraacetate and corn starch into a uniform mixture according to different mass ratios of 2:1, prepare a mixed aqueous solution with a concentration of 20 g / L with the mixture and deionized water, and then add formaldehyde and resorcinol. Using sodium carbonate as a catalyst, the mass ratio of the mixed aqueous solution, formaldehyde, resorcinol, and sodium carbonate is: 1:0.05:0.0125:0.005. Stir evenly at a speed of 240 rpm for 30 min, and then ultrasonic at 40 kHz for 30 min; Then inject the mixed solution into a mold, seal it, and treat it at 80 °C for 3 d to generate a wet gel; Soak the wet gel in ethanol for 3 d and repeat 3 times. After CO 2After supercritical drying, it is a mixed aerogel; finally, under nitrogen protection, it is carbonized at 600 °C for 4 h to obtain nitrogen-doped carbon aerogel; the aerogel is crushed into nanoparticles with a particle size of 50 nm for standby; 3.5 parts of diethylene glycol butyl ether, 2 parts of N,N-dimethylacetamide, and 1.5 parts of terpineol are sequentially added to a stirring kettle, the stirring speed is 120 rpm, the temperature is 40 °C, and they are stirred and mixed for 30 min. Then, 0.1 part of polyester acrylate resin and 0.3 part of epoxy acrylate resin are added, and they are stirred and mixed for 1 h at a stirring speed of 60 rpm. Then, 0.01 part of nano-aerogel particles, 0.01 part of antioxidant 1010, and 0.02 part of aluminate coupling agent are added, and they are mixed for 2 h at a stirring speed of 70 rpm to prepare a slurry; the slurry is coated on the surface of metal graphene aluminum foil, the coating thickness is 20 μm, and it is left standing for 2 h; then the foil strip is sent into a high-temperature furnace, the heating rate of the high-temperature furnace is 10 °C / min, it is heated to 350 °C and kept warm for 2 h, then it is cooled to room temperature at a cooling rate of 20 °C / min, and then the foil is inverted to check for damage, and the damaged part is removed with a cutting machine. The foil strip is inspected and packaged and stored in the warehouse to obtain a four-layer composite carbon foil.

[0028] Example 2; (1) Put polymethyl methacrylate powder on the surface of an aluminum foil with a thickness of 40 μm and then put it into a tubular furnace for in-situ chemical vapor reduction. The thickness of the polymethyl methacrylate powder piled up on the surface of the aluminum foil is 3 μm; the reduction temperature is 900 °C, the reduction atmosphere is hydrogen, the protective atmosphere is argon, the flow ratio of hydrogen to argon is 1:1.25, and the gas flow rate is 250 ml / min; the reduction time is 15 min to obtain aluminum foil with three-dimensional graphene attached to the surface.

[0029] (2) The aluminum foil with three-dimensional graphene attached to the surface is modified by the impregnation method. First, aluminum nitrate is dissolved in deionized water to make an aluminum nitrate aqueous solution, and the mass ratio of aluminum nitrate to deionized water is 12:12. Ammonium carbonate is dissolved in deionized water to make an ammonium nitrate aqueous solution, and the mass ratio of ammonium nitrate to deionized water is 12:12; then the aluminum foil with three-dimensional graphene attached to the surface is added to the ammonium carbonate aqueous solution, the solid-liquid ratio is 1:5, and it is stirred at a speed of 120 rpm for 20 min. Then, the aluminum nitrate aqueous solution is slowly added to the ammonium carbonate solution, and it is stirred at 120 rpm for 30 min and then filtered. The filter residue is washed twice with deionized water and dried in a drying oven at 50 °C to obtain modified graphene aluminum foil; 2.7 mmol of Ni(NO 3 ) 2 ·6H 2 0, 1.8 mmol of Al(NO 3 ) 3 ·6H 2Prepare a solution with a concentration of 80 mmol / L by dissolving 0.8648 g of urea in 100 mL of deionized water. After ultrasonic oscillation at 40 kHz for 10 min, a Ni-Al solution is obtained. In the Ni-Al solution, electrodeposit at a constant current of 10 mA for 10 min to deposit Ni-Al on the modified graphene aluminum foil. After the deposition, wash the modified graphene aluminum foil with deposited Ni-Al three times with deionized water and alcohol, and then vacuum dry at 80 °C for 12 h with a vacuum degree of 0.085 MPa to obtain the metal graphene aluminum foil.

[0030] (3) Grind potassium ethylenediaminetetraacetate and corn starch into a uniform mixture according to different mass ratios of 3.5:1. Prepare a mixed aqueous solution with a concentration of 20 g / L by mixing the mixture with deionized water. Then add formaldehyde and resorcinol, and use sodium carbonate as a catalyst. The mass ratio of the mixed aqueous solution, formaldehyde, resorcinol, and sodium carbonate is: 1: 0.05: 0.0125: 0.005. Stir evenly at a speed of 240 rpm for 30 min, and then ultrasonic at 40 kHz for 30 min. Then inject the mixed solution into a mold, seal it, and treat it at 80 °C for 3 d to generate a wet gel. Soak the wet gel in ethanol for 3 d and repeat 3 times. After supercritical drying, the mixed aerogel is obtained. Finally, under nitrogen protection, high-temperature carbonization is carried out at 700 °C for 4 h to obtain the nitrogen-doped carbon aerogel. Crush the aerogel into nanoparticles with a particle size of 50 nm for standby. Add 3.5 parts of diethylene glycol butyl ether, 2 parts of N,N-dimethylacetamide, and 1.5 parts of terpineol into a stirring kettle in sequence. The stirring speed is 120 rpm, the temperature is 40 °C, and stir and mix for 30 min. Then add 0.1 part of polyester acrylate resin and 0.3 part of epoxy acrylate resin, and stir and mix at a stirring speed of 60 rpm for 1 h. Then add 0.03 part of nano-aerogel particles, 0.01 part of antioxidant 1010, and 0.02 part of aluminate coupling agent, and mix at a stirring speed of 70 rpm for 2 h to prepare a slurry. Coat the slurry on the surface of the metal graphene aluminum foil with a coating thickness of 25 μm, and let it stand for 2 h. Then send the foil strip into a high-temperature furnace. The heating rate of the high-temperature furnace is 10 °C / min, heat up to 350 °C and keep it warm for 2 h, then cool down to room temperature at a cooling rate of 20 °C / min. Then pour out the foil to check for damage, and use a cutting machine to remove the damaged part. Inspect the foil strip and package it and store it in the warehouse to obtain the four-layer composite carbon foil. 2 After supercritical drying, the mixed aerogel is obtained. Finally, under nitrogen protection, high-temperature carbonization is carried out at 700 °C for 4 h to obtain the nitrogen-doped carbon aerogel. Crush the aerogel into nanoparticles with a particle size of 50 nm for standby. Add 3.5 parts of diethylene glycol butyl ether, 2 parts of N,N-dimethylacetamide, and 1.5 parts of terpineol into a stirring kettle in sequence. The stirring speed is 120 rpm, the temperature is 40 °C, and stir and mix for 30 min. Then add 0.1 part of polyester acrylate resin and 0.3 part of epoxy acrylate resin, and stir and mix at a stirring speed of 60 rpm for 1 h. Then add 0.03 part of nano-aerogel particles, 0.01 part of antioxidant 1010, and 0.02 part of aluminate coupling agent, and mix at a stirring speed of 70 rpm for 2 h to prepare a slurry. Coat the slurry on the surface of the metal graphene aluminum foil with a coating thickness of 25 μm, and let it stand for 2 h. Then send the foil strip into a high-temperature furnace. The heating rate of the high-temperature furnace is 10 °C / min, heat up to 350 °C and keep it warm for 2 h, then cool down to room temperature at a cooling rate of 20 °C / min. Then pour out the foil to check for damage, and use a cutting machine to remove the damaged part. Inspect the foil strip and package it and store it in the warehouse to obtain the four-layer composite carbon foil.

[0031] Example 3; (1) Place the polymethyl methacrylate powder on the surface of an aluminum foil with a thickness of 60 μm and then put it into a tube furnace for in-situ chemical vapor reduction. The thickness of the polymethyl methacrylate powder piled up on the surface of the aluminum foil is 5 μm. The reduction temperature is 950 °C, the reduction atmosphere is hydrogen, the protective atmosphere is argon, the flow ratio of hydrogen to argon is 1:2, and the gas flow rate is 300 ml / min. The reduction time is 20 min to obtain the aluminum foil with three-dimensional graphene attached to the surface.

[0032] (2) The aluminum foil with three-dimensional graphene attached to its surface is modified by the impregnation method. First, aluminum nitrate is dissolved in deionized water to form an aluminum nitrate aqueous solution, and the mass ratio of aluminum nitrate to deionized water is 12:24. Ammonium carbonate is dissolved in deionized water to form an ammonium carbonate aqueous solution, and the mass ratio of ammonium carbonate to deionized water is 12:24. Then, the aluminum foil with three-dimensional graphene attached to its surface is added to the ammonium carbonate aqueous solution, with a solid-liquid ratio of 1:5, and stirred at a speed of 120 rpm for 20 min. Then, the aluminum nitrate aqueous solution is slowly added to the ammonium carbonate solution, stirred at 120 rpm for 30 min, and then filtered. The filter product is washed twice with deionized water and dried in an oven at 50 °C to obtain the modified graphene aluminum foil. 3 ) 2 ·6H 2 0, 2.7 mmol of Al(NO 3 ) 3 ·6H 2 0 are formulated into a solution with a concentration of 80 mmol / L. 0.8648 g of urea is added and dissolved in 100 mL of deionized water. After ultrasonic oscillation at 40 kHz for 10 min, a Ni-Al solution is prepared. In the Ni-Al solution, electroplating is carried out at a constant current of 10 mA for 10 min, and Ni-Al is deposited on the modified graphene aluminum foil. After the deposition, the modified graphene aluminum foil deposited with Ni-Al is washed three times with deionized water and alcohol, and then vacuum dried at 80 °C for 12 h, with a vacuum degree of 0.085 MPa, to obtain the metal graphene aluminum foil.

[0033] (3) Potassium ethylenediaminetetraacetate and corn starch are ground into a uniform mixture according to different mass ratios of 5:1. The mixture and deionized water are prepared into a mixed aqueous solution with a concentration of 20 g / L. Then, formaldehyde and resorcinol are added. Using sodium carbonate as a catalyst, the mass ratio of the mixed aqueous solution, formaldehyde, resorcinol, and sodium carbonate is 1:0.05:0.0125:0.005. Stir at a speed of 240 rpm for 30 min to make it uniform, and then carry out ultrasonic treatment at 40 kHz for 30 min. Then, the mixed solution is injected into a mold, sealed, and treated at 80 °C for 3 d to generate a wet gel. The wet gel is soaked in ethanol for 3 d and repeated three times. After passing through CO 2After supercritical drying, it is a mixed aerogel; finally, under nitrogen protection, it is carbonized at 800 °C for 4 h to obtain nitrogen-doped carbon aerogel; the aerogel is broken into nanoparticles with a particle size of 50 nm for standby; 3.5 parts of diethylene glycol butyl ether, 2 parts of N,N-dimethylacetamide, and 1.5 parts of terpineol are added to the stirring kettle in sequence, the stirring speed is 120 rpm, the temperature is 40 °C, and they are stirred and mixed for 30 min. Then, 0.1 part of polyester acrylate resin and 0.3 part of epoxy acrylate resin are added, and they are stirred and mixed for 1 h at a stirring speed of 60 rpm. Then, 0.05 part of nano-aerogel particles, 0.01 part of antioxidant 1010, and 0.02 part of aluminate coupling agent are added, and they are mixed for 2 h at a stirring speed of 70 rpm to prepare a slurry; the slurry is coated on the surface of the metal graphene aluminum foil, the coating thickness is 30 μm, and it is left standing for 2 h; then the foil tape is sent into a high-temperature furnace, the heating rate of the high-temperature furnace is 10 °C / min, it is heated to 350 °C and kept warm for 2 h, and then it is cooled to room temperature at a cooling rate of 20 °C / min. Then, the foil is poured out to check for damage, and the damaged part is removed with a cutting machine. The foil tape is inspected and packaged and stored in the warehouse to obtain a four-layer composite carbon foil.

[0034] Comparative Example 1; The difference between Comparative Example 1 and Example 2 is that step (1) is not included, and steps (2) and (3) are changed to: (2) The aluminum foil is modified by the impregnation method. First, aluminum nitrate is dissolved in deionized water to make an aluminum nitrate aqueous solution, and the mass ratio of aluminum nitrate to deionized water is 12:12. Ammonium carbonate is dissolved in deionized water to make an ammonium nitrate aqueous solution, and the mass ratio of ammonium nitrate to deionized water is 12:12; then the aluminum foil is added to the ammonium carbonate aqueous solution, the solid-liquid ratio is 1:5, and it is stirred at a speed of 120 rpm for 20 min. Then, the aluminum nitrate aqueous solution is slowly added to the ammonium carbonate solution, stirred at 120 rpm for 30 min and then filtered. The filter residue is washed 2 times with deionized water and dried in a drying oven at 50 °C to obtain the modified aluminum foil; 3 ) 2 ·6H 2 0, 1.8 mmol Al(NO 3 ) 3 ·6H 2 0 are formulated into a solution with a concentration of 80 mmol / L, 0.8648 g of urea is added and dissolved in 100 mL of deionized water, and after ultrasonic oscillation at 40 kHz for 10 min, a Ni-Al solution is prepared; in the Ni-Al solution, electrodeposition is carried out at a constant current of 10 mA for 10 min, and Ni-Al is deposited on the modified aluminum foil. After the deposition is completed, the modified aluminum foil deposited with Ni-Al is washed 3 times with deionized water and alcohol, and then vacuum dried at 80 °C for 12 h, and the vacuum degree is 0.085 MPa, that is, the metal aluminum foil is obtained;

[0035] (3) Grind dipotassium ethylenediaminetetraacetate and corn starch into a uniform mixture according to different mass ratios of 3.5:1. Prepare a mixed aqueous solution with a concentration of 20 g / L from the mixture and deionized water, then add formaldehyde and resorcinol. Using sodium carbonate as a catalyst, the mass ratio of the mixed aqueous solution, formaldehyde, resorcinol, and sodium carbonate is: 1:0.05:0.0125:0.005. Stir evenly at a speed of 240 rpm for 30 min, and then ultrasonicate at 40 kHz for 30 min; then inject the mixed solution into a mold, seal it, and treat it at 80 °C for 3 d to generate a wet gel; soak the wet gel in ethanol for 3 d and repeat 3 times. After CO 2 supercritical drying, that is, a mixed aerogel; finally, under nitrogen protection, carbonize at a high temperature of 700 °C for 4 h to obtain a nitrogen-doped carbon aerogel; crush the aerogel into nanoparticles with a particle size of 50 nm for standby; add 3.5 parts of diethylene glycol butyl ether, 2 parts of N,N-dimethylacetamide, and 1.5 parts of terpineol to the stirring kettle in sequence, with a stirring speed of 120 rpm and a temperature of 40 °C, stir and mix for 30 min, then add 0.1 part of polyester acrylate resin and 0.3 part of epoxy acrylate resin, stir and mix for 1 h at a stirring speed of 60 rpm, and then add 0.03 part of nano-aerogel particles, 0.01 part of antioxidant 1010, and 0.02 part of aluminate coupling agent, and mix at a stirring speed of 70 rpm for 2 h to prepare a slurry; coat the slurry on the surface of the metal aluminum foil with a coating thickness of 25 μm, and let it stand for 2 h; then send the foil tape into a high-temperature furnace, with a heating rate of the high-temperature furnace of 10 °C / min, heat up to 350 °C and hold for 2 h, and then cool down to room temperature at a cooling rate of 20 °C / min. Then, pour out the foil to check for damage, and use a cutting machine to remove the damaged part, inspect the foil tape, and package it and store it in the warehouse to obtain a three-layer composite carbon foil; the remaining steps are the same as in Example 2.

[0036] Comparative Example 2; The difference between Comparative Example 2 and Example 2 lies in step (2). Modify step (2) as follows: Dissolve 2.7 mmol of Ni(NO 3 ) 2 ·6H 2 0 and 1.8 mmol of Al(NO 3 ) 3 ·6H 2 0 to form a solution with a concentration of 80 mmol / L. Add 0.8648 g of urea and dissolve it in 100 mL of deionized water. After ultrasonic oscillation at 40 kHz for 10 min, a Ni-Al solution is prepared; in the Ni-Al solution, electro-deposit at a constant current of 10 mA for 10 min to deposit Ni-Al on the graphene aluminum foil. After the deposition, wash the modified graphene aluminum foil deposited with Ni-Al 3 times with deionized water and alcohol, and then vacuum dry at 80 °C for 12 h with a vacuum degree of 0.085 MPa to obtain a metal graphene aluminum foil; the remaining steps are the same as in Example 2.

[0037] Comparative Example 3; The difference between Comparative Example 3 and Example 2 lies in the differences in steps (2) and (3). Steps (2) and (3) are changed to: (2) The aluminum foil with three-dimensional graphene attached to its surface is modified by the impregnation method. First, aluminum nitrate is dissolved in deionized water to form an aluminum nitrate aqueous solution, and the mass ratio of aluminum nitrate to deionized water is 12:12. Ammonium carbonate is dissolved in deionized water to form an ammonium nitrate aqueous solution, and the mass ratio of ammonium nitrate to deionized water is 12:12. Then, the aluminum foil with three-dimensional graphene attached to its surface is added to the ammonium carbonate aqueous solution, and the solid-liquid ratio is 1:5. Stir at a speed of 120 rpm for 20 min, and then slowly add the aluminum nitrate aqueous solution to the ammonium carbonate solution. After stirring at 120 rpm for 30 min, filter, wash the filtrate with deionized water 2 times, and dry it in a drying oven at 50 °C to obtain the modified graphene aluminum foil;

[0038] (3) Potassium ethylenediaminetetraacetate and corn starch are ground into a uniform mixture according to different mass ratios of 3.5:1. The mixture and deionized water are prepared into a mixed aqueous solution with a concentration of 20 g / L, and then formaldehyde and resorcinol are added. Using sodium carbonate as a catalyst, the mass ratio of the mixed aqueous solution, formaldehyde, resorcinol, and sodium carbonate is: 1:0.05:0.0125:0.005. Stir at a speed of 240 rpm for 30 min to make it uniform, and then ultrasonicate at 40 kHz for 30 min. Then, inject the mixed solution into a mold, seal it, and treat it at 80 °C for 3 d to generate a wet gel. Soak the wet gel in ethanol for 3 d, repeat 3 times, and after CO 2 supercritical drying, namely the mixed aerogel; Finally, under nitrogen protection, high-temperature carbonization is carried out at 700 °C for 4 h to obtain nitrogen-doped carbon aerogel; The aerogel is broken into nanoparticles with a particle size of 50 nm for standby. 3.5 parts of diethylene glycol butyl ether, 2 parts of N,N-dimethylacetamide, and 1.5 parts of terpineol are added to the stirring kettle in sequence, the stirring speed is 120 rpm, the temperature is 40 °C, and stir and mix for 30 min. Then, add 0.1 part of polyester acrylate resin and 0.3 part of epoxy acrylate resin, and stir and mix at a stirring speed of 60 rpm for 1 h. Then, add 0.03 part of nano-aerogel particles, 0.01 part of antioxidant 1010, and 0.02 part of aluminate coupling agent, and mix at a stirring speed of 70 rpm for 2 h to obtain a slurry. Coat the slurry on the surface of the modified graphene aluminum foil, and the coating thickness is 25 μm, and let it stand for 2 h. Then, send the foil tape into a high-temperature furnace, the heating rate of the high-temperature furnace is 10 °C / min, heat up to 350 °C and keep it warm for 2 h, and then cool down to room temperature at a cooling rate of 20 °C / min. Then, pour out the foil to check for damage, and use a cutting machine to remove the damaged part, inspect the foil tape and package it for storage to obtain a three-layer composite carbon foil; The remaining steps are the same as those in Example 2.

[0039] Comparative Example 4; The difference between Comparative Example 4 and Example 2 lies in step (3). Step (3) is changed to: Prepare an aqueous graphene solution with a concentration of 20 g / L by mixing graphene and deionized water, then add formaldehyde and resorcinol, and use sodium carbonate as a catalyst. The mass ratio of the aqueous graphene solution, formaldehyde, resorcinol, and sodium carbonate is 1:0.05:0.0125:0.005. Stir evenly at a speed of 240 rpm for 30 min, and then ultrasonicate at 40 kHz for 30 min; then inject the mixture into a mold, seal it, and treat it at 80 °C for 3 days to form a wet gel; soak the wet gel in ethanol for 3 days, repeat 3 times, and pass through CO 2 After supercritical drying, it is a mixed aerogel; finally, under nitrogen protection, it is carbonized at a high temperature of 700 °C for 4 h to obtain a nitrogen-doped carbon aerogel; crush the aerogel into nanoparticles with a particle size of 50 nm for standby; add 3.5 parts of diethylene glycol butyl ether, 2 parts of N,N-dimethylacetamide, and 1.5 parts of terpineol to the stirring kettle in sequence, with a stirring speed of 120 rpm and a temperature of 40 °C, stir and mix for 30 min, then add 0.1 part of polyester acrylate resin and 0.3 part of epoxy acrylate resin, stir and mix at a stirring speed of 60 rpm for 1 h, then add 0.03 part of nano-aerogel particles, 0.01 part of antioxidant 1010, and 0.02 part of aluminate coupling agent, and mix at a stirring speed of 70 rpm for 2 h to prepare a slurry; coat the slurry on the surface of the metal graphene aluminum foil, with a coating thickness of 25 μm, and let it stand for 2 h; then send the foil tape into a high-temperature furnace, with a heating rate of the high-temperature furnace of 10 °C / min, heat up to 350 °C and keep it warm for 2 h, then cool down to room temperature at a cooling rate of 20 °C / min, then pour out the foil to check for damage, and use a cutting machine to remove the damaged part, inspect the foil tape and package it for storage to obtain a four-layer composite carbon foil; the remaining steps are the same as in Example 2.

[0040] Effect Example

[0041] The following Table 1 gives the performance analysis results of a high-adhesion solid-state capacitor carbon foil using Examples 1 to 3 and Comparative Examples 1 to 4 of the present invention.

[0042] Table 1

[0043]

[0044] From the comparison of the experimental data of the capacitance of the examples and the comparative examples, it can be found that in the present invention, polymethyl methacrylate is used as a carbon source on the surface of the aluminum foil, and through in-situ chemical vapor reduction method, the decomposed carbon atoms in-situ generate a three-dimensional graphene layer on the surface of the aluminum foil. The three-dimensional graphene layer with low density has better electrochemical performance than two-dimensional graphene, and the in-situ grown graphene has a strong binding force with the surface of the aluminum foil. Secondly, aluminum nitrate and ammonium nitrate are used to modify the graphene layer, and then a continuous sheet-like Ni-Al layer is prepared on the graphene layer by electrochemical deposition. The three-dimensional graphene and the continuous metal sheet layer provide rich redox active sites, combining the conductivity of graphene and the redox characteristics of metal oxides. The synergistic effect of the two significantly improves the ion diffusion ability of the carbon foil. Finally, potassium ethylenediaminetetraacetate is used as a nitrogen source, mixed with corn starch to prepare an aerogel, and then a structurally stable nitrogen-doped carbon aerogel is obtained by high-temperature carbonization. It is made into a powder and coated on the surface of the Ni-Al layer to prepare a four-layer composite carbon foil. Doping nitrogen atoms can change the surface chemical properties of the carbon aerogel material, improve the wettability of the electrode, and increase the diffusion rate of electrolyte ions. At the same time, nitrogen atoms can form nitrogen-containing functional groups with the carbon aerogel skeleton, and these nitrogen-containing functional groups can make the electrode material generate pseudocapacitance, thereby increasing the specific capacitance of the material, and thus improving the overall electrochemical performance of the carbon foil. From the comparison of the experimental data of the capacity retention rate of the 500h 125°C accelerated life experiment of the examples and the comparative examples, it can be found that the combination of the deposition effect of the second and third layers and the coating effect of the fourth layer of the present invention makes the composite carbon foils of the present invention firmly bonded to each other and not easily fall off.

[0045] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be construed as limiting the claimed claim.

Claims

1. A high-adhesion solid capacitor carbon foil production process, characterized in that: The process steps include: (1) placing polymethyl methacrylate powder on the surface of aluminum foil and then placing it in a tube furnace for in-situ chemical vapor reduction; the reduction temperature is 850-950° C., the reducing atmosphere is hydrogen, the protective atmosphere is argon, and the flow ratio of hydrogen to argon is 1:0.5-2; the reduction time is 10-20 minutes, and an aluminum foil with three-dimensional graphene attached to the surface is obtained; (2) adding an aqueous solution of ammonium carbonate to an aluminum foil with three-dimensional graphene attached to the surface at a solid-liquid ratio of 1:5, stirring at 120 rpm for 20 min, then slowly adding an aqueous solution of aluminum nitrate to the ammonium carbonate solution, stirring at 120 rpm for 30 min, filtering, washing the filtrate twice with deionized water, and drying in a 50°C drying oven to obtain a modified graphene aluminum foil; in a Ni-Al solution, electroplating at a constant current of 10 mA for 10 min, depositing Ni-Al on the modified graphene aluminum foil, washing the modified graphene aluminum foil deposited with Ni-Al with deionized water and alcohol three times after the deposition, and then vacuum drying at 80°C for 12 h to obtain a metallic graphene aluminum foil; (3) 3.5 parts of diethylene glycol butyl ether, 2 parts of N,N-dimethylacetamide and 1.5 parts of pineol were added into a stirring kettle in sequence, with a stirring speed of 120 rpm and a temperature of 40°C, and the mixture was stirred and mixed for 30 minutes. Then, 0.1 parts of polyester acrylic resin and 0.3 parts of epoxy acrylic resin were added, and the mixture was stirred and mixed for 1 hour at a stirring speed of 60 rpm. Then, 0.01-0.05 parts of nano aerogel particles, 0.01 parts of antioxidant 1010 and 0.02 parts of aluminate coupling agent were added, and the mixture was stirred and mixed for 2 hours at a stirring speed of 70 rpm to obtain a slurry. The slurry was coated on the surface of the metal graphene aluminum foil to obtain a four-layer composite carbon foil.

2. The high adhesion solid capacitor carbon foil production process according to claim 1, characterized in that: In the step (1), the thickness of the aluminum foil is 20-60 μm, and the thickness of the polymethyl methacrylate powder deposited on the surface of the aluminum foil is 1-5 μm.

3. The high adhesion solid capacitor carbon foil production process according to claim 1, characterized in that: The gas flow rate in step (1) is 200-300 ml / min.

4. The high adhesion solid capacitor carbon foil production process according to claim 1, characterized in that: In the step (2), the aluminum foil with three-dimensional graphene attached to the surface is modified by an immersion method, aluminum nitrate is dissolved in deionized water to prepare an aluminum nitrate aqueous solution, and the mass ratio of aluminum nitrate to deionized water is 12:1-24; ammonium carbonate is dissolved in deionized water to prepare an ammonium nitrate aqueous solution, and the mass ratio of ammonium nitrate to deionized water is 12:1-24.

5. The high adhesion solid capacitor carbon foil production process according to claim 1, characterized in that: The preparation method of the Ni-Al solution in step (2) is as follows: 2.7 mmol Ni(NO3)2·6H20 and 0.9-2.7 mmol Al(NO3)3·6H20 are prepared into a solution with a concentration of 80 mmol / L, 0.8648 g urea is added and dissolved in 100 mL deionized water, and the solution is ultrasonically shaken at 40 kHz for 10 minutes to obtain a Ni-Al solution.

6. The high adhesion solid capacitor carbon foil production process according to claim 1, characterized in that: The vacuum degree of vacuum drying in step (2) is 0.085 MPa.

7. The high adhesion solid capacitor carbon foil production process according to claim 1, characterized in that: In the step (3), dipotassium ethylenediaminetetraacetate and corn starch are ground into a uniform mixture in different mass ratios of 2-5:1, the mixture is mixed with deionized water to prepare a mixed aqueous solution, formaldehyde and m-diphenol are added, sodium carbonate is used as a catalyst, and the mixture is stirred at 240 rpm for 30 minutes, and then ultrasonicated at 40 kHz for 30 minutes; the mixed solution is then injected into a mold, sealed, and treated at 80° C. for 3 days to generate a wet gel; The wet gel was soaked in ethanol for 3 days, repeated 3 times, and then dried with CO2 supercritical fluid to obtain a mixed aerogel. Finally, the aerogel was carbonized at 600-800°C for 4 hours under nitrogen protection to obtain nitrogen-doped carbon aerogel. The aerogel was crushed into particles with a particle size of 50 nm for later use.

8. The high adhesion solid capacitor carbon foil production process according to claim 7, characterized in that: The concentration of the mixed aqueous solution is 20 g / L.

9. The high adhesion solid capacitor carbon foil production process according to claim 7, characterized in that: The mass ratio of the mixed aqueous solution, formaldehyde, resorcinol and sodium carbonate is: 1:0.05:0.0125:0.

005.

10. The high adhesion solid capacitor carbon foil production process according to claim 1, characterized in that: In the step (3), the slurry is coated with a coating thickness of 20-30 μm and is left to stand for 2 hours. After the coating, the foil strip is sent to a high-temperature furnace with a heating rate of 10°C / min, heated to 350°C and kept for 2 hours, and then cooled to room temperature at a cooling rate of 20°C / min. The foil strip is then turned over to check for damage, and the damage is removed with a cutter. The foil strip is inspected and packaged for storage.

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