High-capacity carbon-titanium composite electrode foil and manufacturing method thereof

Abstract

The invention relates to the technical field of electrode foil manufacturing, in particular to a high-capacity carbon-titanium composite electrode foil and a manufacturing method thereof. The manufacturing method comprises the following steps: S1, pretreatment: immersing an aluminum foil in a mixed solution of 10% sulfuric acid and 0.5% hydrofluoric acid for 30 s, and then taking out the aluminum foil to complete the pretreatment step; s2, micro-etching: heating the etching solution to 45-55 DEG C, performing micro-etching by using the etching solution under ultrasonic waves to form micropores with the pore diameter of 0.5-2 microns in the aluminum foil, washing by using deionized water after etching is completed, and drying at 80 DEG C to obtain micro-etched aluminum foil; and S3, constructing a carbon-titanium active layer. According to the high-capacity carbon-titanium composite electrode foil and the manufacturing method thereof, the problems that in the prior art, the difference between the thermal expansion coefficients of titanium and a carbon material is large, interface stress concentration is likely to be caused, and a porous structure formed through micro-etching easily causes cracking of a titanium substrate under cyclic stress are solved.

Description

Technical Field

[0001] The present application relates to the technical field of electrode foil manufacturing, and in particular to a high-capacity carbon-titanium composite electrode foil and a manufacturing method thereof. Background Art

[0002] Aluminum foil has high conductivity (conductivity of about 37.7MS / m), lightweight (density of 2.7g / cm 3 ) and low cost advantages, becoming the core material of current collectors for energy storage devices. Its performance directly affects the energy density and cycle life of batteries and capacitors. However, traditional aluminum foil electrodes have insufficient specific capacity (usually <10cm 2 / cm 3 ) and high interface impedance, which limit its application in high-end energy storage devices.

[0003] Related technologies usually include forming a microporous structure on the surface of aluminum foil through chemical or electrochemical etching to expand the specific surface area, and improving the dielectric properties by coating the aluminum foil surface with titanium oxide. However, the former is prone to cause the mechanical properties of the aluminum foil to deteriorate when the micropores exceed 50μm, resulting in cracking of the electrode during the charge and discharge cycle. In addition, the inner wall of the micropores lacks active sites and has poor electrolyte wettability, which limits the ion transfer efficiency. In the latter method, although titanium dioxide has a high dielectric constant, it is easy to undergo hydration reaction in acidic electrolytes, resulting in capacity decay, and the physically adsorbed coating will have the risk of falling off during the cycle.

[0004] In recent years, the research on carbon-titanium composite electrode foil has made significant progress through microstructure control and interface optimization. The titanium-carbon gradient layer has both high dielectric properties (TiO2) and high conductivity (carbon), which can achieve rapid charge migration at high frequencies. The mass specific capacity in supercapacitors can reach 600F / g, which is more than 3 times higher than that of pure aluminum foil. It can also maintain a relatively stable capacity after multiple cycles, which is far superior to traditional TiO2 coatings. However, the thermal expansion coefficients of titanium and carbon materials are quite different (titanium: 8.6×10 -6 / ℃, carbon: 2.2×10 -6 / ℃), which can easily lead to interface stress concentration, and the porous structure formed by micro-etching can easily cause the titanium substrate to crack under cyclic stress. Summary of the Invention

[0005] The present application provides a high-capacity carbon-titanium composite electrode foil and a method for manufacturing the same, in order to solve the problems in the related art in that the thermal expansion coefficients of titanium and carbon materials are quite different, which easily leads to interface stress concentration, and the porous structure formed by micro-etching easily causes the titanium substrate to crack under cyclic stress.

[0006] In a first aspect, a method for manufacturing a high-capacity carbon-titanium composite electrode foil is provided, comprising the following steps:

[0007] S1. Pretreatment: Immerse the aluminum foil in a mixture of 10% sulfuric acid and 0.5% hydrofluoric acid for 30 seconds and then remove it to complete the pretreatment step;

[0008] S2. Micro-etching: The etching solution is heated to 45-55°C and micro-etched using the etching solution under ultrasonic conditions to form micropores with a pore size of 0.5-2 μm on the aluminum foil. After etching, the aluminum foil is washed with deionized water and dried at 80°C to obtain micro-etched aluminum foil. The etching time is 8-12 minutes and the spray pressure is 2-3 kg / cm 2 ;

[0009] S3. Construction of carbon-titanium active layer:

[0010] S301, bottom layer construction:

[0011] After etching the micro-etched aluminum foil with argon plasma for 5 minutes, argon and methane were introduced to sputter TiC nanocrystals onto the surface of the micro-etched aluminum foil to obtain a TiC nanocrystal bottom layer;

[0012] S302, middle layer construction:

[0013] The carbon-titanium composite slurry was coated on the TiC nanocrystalline bottom layer, vacuum dried at 80°C for 12 hours, then cured at 300°C in a nitrogen atmosphere for 1 hour, then kept at 500°C in an Ar / H2 / NH3 mixture for 2 hours, and then kept at 600°C in a vacuum environment for 1 hour. After cooling, the intermediate layer was constructed. The carbon-titanium composite slurry coating thickness was 12 to 60 μm.

[0014] S303, surface construction:

[0015] The electrode foil after the intermediate layer construction obtained in S302 is immersed in the coating sol, coated by dip coating, dried at room temperature for 30 minutes, and then dried at 60°C for 1 hour. Subsequently, the temperature is raised to 300°C in a tube furnace, kept warm for 1 hour under a nitrogen atmosphere, and then continued to be raised to 600°C, kept warm for 2 hours in an argon atmosphere, and cooled to room temperature to complete the surface layer construction, thereby obtaining a high-capacity carbon-titanium composite electrode foil, wherein the coating thickness is 5 to 10 μm;

[0016] The coating sol comprises tetrabutyl titanate, glucose, urea and ethanol, wherein the mass volume ratio of the tetrabutyl titanate, glucose, urea and ethanol is 1 g:2 g:3 g:10 mL. The manufacturing method of the coating sol comprises:

[0017] Glucose, urea and ethanol were mixed and stirred to dissolve, and tetrabutyl titanate was added dropwise. The mixture was stirred for 30 minutes to obtain a coating sol.

[0018] Preferably, after S303, it further includes:

[0019] S4. Post-treatment: spraying cerium oxide sol on the surface layer and drying it at 60° C. for 20 minutes to complete the post-treatment. The spraying thickness of the cerium oxide sol is 100 nm.

[0020] Preferably, the method for preparing cerium oxide sol comprises the following steps:

[0021] After dissolving cerium nitrate hexahydrate in deionized water, the pH value was adjusted to 9-10 with ammonia water, and the cerium oxide sol was obtained after aging for 24 hours.

[0022] Preferably, the etching solution comprises 30-40 parts of 85% phosphoric acid, 8-15 parts of 65% nitric acid, 1 part of hydroxyethyl cellulose, 20-30 parts of 1% chitosan hydrochloric acid solution, and 30-40 parts of deionized water.

[0023] Preferably, in S302, the carbon-titanium composite slurry comprises graphene / TiC core-shell particles, a titanate coupling agent, a phenolic resin, and anhydrous ethanol in a mass ratio of (8-9):1:9:3, and the manufacturing method thereof comprises:

[0024] After dispersing the titanate coupling agent in anhydrous ethanol, the graphene / TiC core-shell particles were added and ball-milled for 2 h. Subsequently, the phenolic resin was added and ball-milled for 1 h to obtain a carbon-titanium composite slurry.

[0025] Preferably, the method for manufacturing the graphene / TiC core-shell particles comprises:

[0026] Graphene oxide was dispersed in deionized water and ultrasonically dispersed for 30 min to obtain a 100 mg / mL dispersion.

[0027] TiC nanocrystals were added to the dispersion and magnetically stirred for 2 hours. Ammonia water was then added dropwise until the pH was 9. Hydrazine hydrate was added and the mixture was reacted in a water bath at 60°C for 12 hours. The mixture was then centrifuged. The separated solid product was washed with deionized water and vacuum dried at 60°C for 18 hours to obtain graphene / TiC core-shell particles. The mass ratio of the TiC nanocrystals to the graphene oxide was 1:1, and the mass-to-volume ratio of the graphene oxide to the hydrazine hydrate was 25 g:1 mL.

[0028] Preferably, after S2 and before S3, the process further includes the following steps:

[0029] The micro-etched aluminum foil was immersed in the dopamine solution and oscillated at room temperature for 2 h. It was then rinsed with deionized water and dried. It was then immersed in the glycyrrhizic acid solution for 5 min and then taken out and dried at 80°C.

[0030] Preferably, the concentration of the dopamine solution is 2 mg / mL, and the method for preparing the dopamine solution comprises the following steps: dissolving dopamine hydrochloride in Tris-HCl buffer to obtain a dopamine solution, wherein the Tris-HCl buffer has a pH of 8.5 and a concentration of 10 mmol / L.

[0031] Preferably, the aluminum foil is 1050 aluminum foil, 1070 aluminum foil or 1090 aluminum foil with a thickness of 20 to 30 μm.

[0032] In a second aspect, a high-capacity carbon-titanium composite electrode foil is provided, which is manufactured by any of the above-described methods for manufacturing a high-capacity carbon-titanium composite electrode foil.

[0033] The beneficial effects of the technical solution provided by this application include:

[0034] The present application provides a high-capacity carbon-titanium composite electrode foil and a manufacturing method thereof. Surface etching is used to construct a high-roughness substrate, increase the specific surface area, and retain tensile strength. Furthermore, magnetron sputtering is used to form a TiC nanocrystalline bottom layer, a carbon-titanium composite slurry middle layer, and a surface layer. In the sol of the surface layer, ethanol is used as a solvent, tetrabutyl titanate is hydrolyzed to generate TiO2, glucose is carbonized to generate C, and urea is decomposed to provide N. The latter three react with a reduction carbonization reaction at high temperature to generate TiC. Simultaneously, N is incorporated into the lattice through substitution or interstitial mechanisms to form N-TiC. During the sol-gel process, titanium hydroxyl groups form chemical bonds (Ti-O-Al) with hydroxyl groups on the surface of the aluminum foil (exposed after etching). Simultaneously, the carbon network after carbonization is mechanically interlocked with the aluminum foil to improve the adhesion of the coating. Therefore, the problem in the related art that the thermal expansion coefficients of titanium and carbon materials are greatly different, which easily leads to interfacial stress concentration, and the porous structure formed by micro-etching easily causes the titanium substrate to crack under cyclic stress can be solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0036] Figure 1 A flow chart of the method for manufacturing the high-capacity carbon-titanium composite electrode foil provided in this application;

[0037] Figure 2 This is a specific flow chart of S3 in the method for manufacturing the high-capacity carbon-titanium composite electrode foil provided in this application. DETAILED DESCRIPTION

[0038] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0039] See also Figure 1-2 As shown, the present application provides a high-capacity carbon-titanium composite electrode foil (hereinafter referred to as electrode foil) and a manufacturing method thereof.

[0040] In the examples and comparative examples provided in this application, the aluminum foil used has an Al content of ≥99.7%, and the phenolic resin used is PR-2088.

[0041] In the S1 pretreatment step, 10% sulfuric acid and 0.5% hydrofluoric acid refer to the volume ratio of sulfuric acid / hydrofluoric acid in deionized water.

[0042] Example 1

[0043] In this embodiment, the method for manufacturing a high-capacity carbon-titanium composite electrode foil includes the following steps:

[0044] S1. Pretreatment: Immerse a 25 μm thick 1070 aluminum foil in a mixture of 10% sulfuric acid and 0.5% hydrofluoric acid for 30 seconds to remove the oxide layer and then take it out to complete the pretreatment step;

[0045] S2. Micro-etching: The etching solution was heated to 50°C and micro-etched using the etching solution under ultrasonic conditions to form micropores with a pore size of 1 μm (aspect ratio of 3:1) on the aluminum foil. After etching, the aluminum foil was washed with deionized water and dried at 80°C to obtain micro-etched aluminum foil. The etching time was 10 min and the spray pressure was 2.5 kg / cm 2 ;

[0046] The micro-etched aluminum foil was immersed in a 2 mg / mL dopamine solution and oscillated at room temperature for 2 h. The foil was then rinsed with deionized water and dried. The foil was then immersed in a glycyrrhizic acid solution for 5 min and then dried at 80°C.

[0047] S3. Construction of carbon-titanium active layer:

[0048] S301, bottom layer construction:

[0049] After etching the micro-etched aluminum foil with argon plasma for 5 minutes, argon and methane were introduced to sputter TiC nanocrystals onto the surface of the micro-etched aluminum foil to obtain a TiC nanocrystal bottom layer;

[0050] S302, middle layer construction:

[0051] A carbon-titanium composite slurry was applied to the TiC nanocrystalline bottom layer using an applicator, vacuum dried at 80°C for 12 hours, then cured at 300°C in a nitrogen atmosphere for 1 hour, then kept at 500°C for 2 hours in an Ar / H2 / NH3 mixture (Ar:H2:NH3=6:3:1), and then kept at 600°C in a vacuum environment for 1 hour. After cooling, the intermediate layer was constructed. The coating thickness of the carbon-titanium composite slurry was 40 μm, and the dry film thickness (the thickness of the carbon-titanium composite slurry after drying) was 8 μm.

[0052] S303, surface construction:

[0053] The electrode foil after the intermediate layer construction obtained in S302 was immersed in the coating sol, coated by dip coating, dried at room temperature for 30 minutes, and then dried at 60°C for 1 hour. Subsequently, the temperature was raised to 300°C in a tube furnace, kept warm for 1 hour under a nitrogen atmosphere, and then continued to be raised to 600°C, kept warm for 2 hours in an argon atmosphere, and cooled to room temperature to complete the surface layer construction, thereby obtaining a high-capacity carbon-titanium composite electrode foil with a coating thickness of 8 μm.

[0054] The coating sol includes 5 g of tetrabutyl titanate, 10 g of glucose, 15 g of urea and 50 mL of ethanol. The manufacturing method of the coating sol includes:

[0055] Glucose, urea and ethanol were mixed and stirred to dissolve, and tetrabutyl titanate was added dropwise. The mixture was stirred for 30 minutes to obtain a coating sol.

[0056] S4, post-treatment: spraying cerium oxide sol on the surface and drying it at 60°C for 20 minutes to complete the post-treatment. The spraying thickness of cerium oxide sol is 100nm. The cerium oxide sol preparation method includes the following steps:

[0057] After dissolving cerium nitrate hexahydrate in deionized water, the pH value was adjusted to 9 using ammonia water, and the cerium oxide sol was obtained after aging for 24 hours.

[0058] The etching solution used in S2 includes: 35g of 85% phosphoric acid, 10g of 65% nitric acid, 1g of hydroxyethyl cellulose, 25g of 1% chitosan hydrochloric acid solution (0.4g chitosan, 0.2g hydrochloric acid, the remainder is deionized water), and 35g of deionized water.

[0059] The carbon-titanium composite slurry in S302 includes 100g of graphene / TiC core-shell particles, 12g of titanate coupling agent NDZ-101, 108g of phenolic resin and 36g of anhydrous ethanol, and its manufacturing method includes:

[0060] The titanate coupling agent was dispersed in anhydrous ethanol and then ultrasonically dispersed for 15 minutes. Graphene / TiC core-shell particles were added and ball milled for 2 hours (speed 300 rpm). Subsequently, phenolic resin (molecular weight 1000) was added and ball milling was continued for 1 hour to obtain a carbon-titanium composite slurry.

[0061] The method for manufacturing graphene / TiC core-shell particles is as follows:

[0062] Disperse 60 g of graphene oxide in deionized water and ultrasonically disperse for 30 min to obtain a 100 mg / mL dispersion.

[0063] 60 g of TiC nanocrystals were added to the dispersion and magnetically stirred for 2 h. Ammonia water was then added dropwise until the pH was 9, 2.4 mL of hydrazine hydrate was slowly added, and the mixture was reacted in a water bath at 60 ° C for 12 h. The mixture was then centrifuged at 8000 rpm to remove residual ammonia water and hydrazine hydrate. The separated solid product was washed with deionized water and vacuum dried at 60 ° C for 18 h to obtain graphene / TiC core-shell particles.

[0064] The dopamine solution was prepared by dissolving 1 g of dopamine hydrochloride in 500 mL of Tris-HCl buffer to obtain a dopamine solution, wherein the pH of the Tris-HCl buffer was 8.5 and the concentration was 10 mmol / L.

[0065] The glycyrrhizic acid solution was prepared by dissolving 0.2 g of glycyrrhizic acid in a mixture of 50 mL of ethanol and 50 mL of water.

[0066] Example 2

[0067] In the method for manufacturing the high-capacity carbon-titanium composite electrode foil provided in this embodiment, the method is the same as that in Example 1 except that the impregnation with the dopamine solution and the glycyrrhizic acid solution is not performed between steps S2 and S3.

[0068] Example 3

[0069] The manufacturing method of the high-capacity carbon-titanium composite electrode foil provided in this embodiment is consistent with that in Example 1 except that the operation of step S4 is not performed at the end.

[0070] Example 4

[0071] The manufacturing method of the high-capacity carbon-titanium composite electrode foil provided in this embodiment is consistent with that in Example 1 except that the coating thickness of the carbon-titanium composite slurry in step S302 is 60 μm and the dry film thickness (the thickness of the carbon-titanium composite slurry after drying) is 12 μm.

[0072] Example 5

[0073] In this embodiment, a method for manufacturing a high-capacity carbon-titanium composite electrode foil is provided, comprising the following steps:

[0074] S1. Pretreatment: Immerse a 20 μm thick 1050 aluminum foil in a mixture of 10% sulfuric acid and 0.5% hydrofluoric acid for 30 seconds to remove the oxide layer and then take it out to complete the pretreatment step;

[0075] S2. Micro-etching: The etching solution was heated to 45°C and micro-etched using the etching solution under ultrasonic conditions to form micropores with a pore size of 0.5 to 1 μm (aspect ratio of 3:1) on the aluminum foil. After etching, the aluminum foil was washed with deionized water and dried at 80°C to obtain micro-etched aluminum foil. The etching time was 8 minutes and the spray pressure was 2 kg / cm 2 ;

[0076] The micro-etched aluminum foil was immersed in a 2 mg / mL dopamine solution and oscillated at room temperature for 2 h. The foil was then rinsed with deionized water and dried. The foil was then immersed in a glycyrrhizic acid solution for 5 min and then dried at 80°C.

[0077] S3. Construction of carbon-titanium active layer:

[0078] S301, bottom layer construction:

[0079] After etching the micro-etched aluminum foil with argon plasma for 5 minutes, argon and methane were introduced to sputter TiC nanocrystals onto the surface of the micro-etched aluminum foil to obtain a TiC nanocrystal bottom layer;

[0080] S302, middle layer construction:

[0081] A carbon-titanium composite slurry was applied to the TiC nanocrystalline bottom layer using an applicator, vacuum dried at 80°C for 12 hours, then cured at 300°C in a nitrogen atmosphere for 1 hour, then kept at 500°C for 2 hours in an Ar / H2 / NH3 (Ar:H2:NH3=6:3:1) mixed gas, and then kept at 600°C in a vacuum environment for 1 hour. After cooling, the intermediate layer was constructed. The coating thickness of the carbon-titanium composite slurry was 12 μm, and the dry film thickness (the thickness of the carbon-titanium composite slurry after drying) was 3 μm.

[0082] S303, surface construction:

[0083] The electrode foil after the intermediate layer construction obtained in S302 was immersed in the coating sol, coated by dip coating, dried at room temperature for 30 minutes, and then dried at 60°C for 1 hour. Subsequently, the temperature was raised to 300°C in a tube furnace, kept warm for 1 hour under a nitrogen atmosphere, and then continued to be raised to 600°C, kept warm for 2 hours in an argon atmosphere, and cooled to room temperature to complete the surface layer construction, thereby obtaining a high-capacity carbon-titanium composite electrode foil with a coating thickness of 10 μm.

[0084] The coating sol includes 5 g of tetrabutyl titanate, 10 g of glucose, 15 g of urea and 50 mL of ethanol. The manufacturing method of the coating sol includes:

[0085] Glucose, urea and ethanol were mixed and stirred to dissolve, and tetrabutyl titanate was added dropwise. The mixture was stirred for 30 minutes to obtain a coating sol.

[0086] S4, post-treatment: spraying cerium oxide sol on the surface and drying it at 60°C for 20 minutes to complete the post-treatment. The spraying thickness of cerium oxide sol is 100nm. The cerium oxide sol preparation method includes the following steps:

[0087] After dissolving cerium nitrate hexahydrate in deionized water, the pH value was adjusted to 10 using ammonia water, and the cerium oxide sol was obtained after aging for 24 hours.

[0088] The etching solution used in S2 includes: 30g of 85% phosphoric acid, 8g of 65% nitric acid, 1g of hydroxyethyl cellulose, 20g of 1% chitosan hydrochloric acid solution (0.2g chitosan, 0.1g hydrochloric acid, the remainder is deionized water), and 30g of deionized water.

[0089] The carbon-titanium composite slurry in S302 includes 96g of graphene / TiC core-shell particles, 12g of titanate coupling agent NDZ-101, 108g of phenolic resin and 36g of anhydrous ethanol, and its manufacturing method includes:

[0090] The titanate coupling agent was dispersed in anhydrous ethanol and then ultrasonically dispersed for 15 minutes. Graphene / TiC core-shell particles were added and ball milled for 2 hours (speed 300 rpm). Subsequently, phenolic resin (molecular weight 1000) was added and ball milling was continued for 1 hour to obtain a carbon-titanium composite slurry.

[0091] The method for manufacturing the graphene / TiC core-shell particles, and the method for preparing the dopamine solution and the glycyrrhizic acid solution are the same as those in Example 1.

[0092] Example 6

[0093] In this embodiment, the method for manufacturing a high-capacity carbon-titanium composite electrode foil includes the following steps:

[0094] S1. Pretreatment: Immerse a 30 μm thick 1090 aluminum foil in a mixture of 10% sulfuric acid and 0.5% hydrofluoric acid for 30 seconds to remove the oxide layer and then take it out to complete the pretreatment step;

[0095] S2. Micro-etching: The etching solution was heated to 55°C and micro-etched using the etching solution under ultrasonic conditions to form micropores with a pore size of 1 to 2 μm (aspect ratio of 3:1) on the aluminum foil. After etching, the aluminum foil was washed with deionized water and dried at 80°C to obtain micro-etched aluminum foil. The etching time was 12 min and the spray pressure was 3 kg / cm 2 ;

[0096] S3. Construction of carbon-titanium active layer:

[0097] S301, bottom layer construction:

[0098] After etching the micro-etched aluminum foil with argon plasma for 5 minutes, argon and methane were introduced to sputter TiC nanocrystals onto the surface of the micro-etched aluminum foil to obtain a TiC nanocrystal bottom layer;

[0099] S302, middle layer construction:

[0100] A carbon-titanium composite slurry was applied to the TiC nanocrystalline bottom layer using an applicator, vacuum dried at 80°C for 12 hours, then cured at 300°C in a nitrogen atmosphere for 1 hour, then kept at 500°C for 2 hours in an Ar / H2 / NH3 (Ar:H2:NH3=6:3:1) mixed gas, and then kept at 600°C in a vacuum environment for 1 hour. After cooling, the intermediate layer was constructed. The coating thickness of the carbon-titanium composite slurry was 40 μm, and the dry film thickness (the thickness of the carbon-titanium composite slurry after drying) was 8 μm.

[0101] S303, surface construction:

[0102] The electrode foil after the intermediate layer construction obtained in S302 was immersed in the coating sol, coated by dip coating, dried at room temperature for 30 minutes, and then dried at 60°C for 1 hour. Subsequently, the temperature was raised to 300°C in a tube furnace, kept warm for 1 hour under a nitrogen atmosphere, and then continued to be raised to 600°C, kept warm for 2 hours in an argon atmosphere, and cooled to room temperature to complete the surface layer construction, thereby obtaining a high-capacity carbon-titanium composite electrode foil with a coating thickness of 8 μm.

[0103] The coating sol includes 5 g of tetrabutyl titanate, 10 g of glucose, 15 g of urea and 50 mL of ethanol. The manufacturing method of the coating sol includes:

[0104] Glucose, urea and ethanol were mixed and stirred to dissolve, and tetrabutyl titanate was added dropwise. The mixture was stirred for 30 minutes to obtain a coating sol.

[0105] The etching solution used in S2 includes: 35g of 85% phosphoric acid, 10g of 65% nitric acid, 1g of hydroxyethyl cellulose, 25g of 1% chitosan hydrochloric acid solution (0.4g chitosan, 0.2g hydrochloric acid, the remainder is deionized water), and 35g of deionized water.

[0106] The carbon-titanium composite slurry in S302 includes 100g of graphene / TiC core-shell particles, 12g of titanate coupling agent NDZ-101, 108g of phenolic resin and 36g of anhydrous ethanol, and its manufacturing method includes:

[0107] The titanate coupling agent NDZ-101 was dispersed in anhydrous ethanol and then ultrasonically dispersed for 15 minutes. The graphene / TiC core-shell particles were added and ball milled for 2 hours (speed 300 rpm). Subsequently, phenolic resin (molecular weight 1000) was added and ball milling was continued for 1 hour to obtain a carbon-titanium composite slurry.

[0108] The method for manufacturing graphene / TiC core-shell particles is as follows:

[0109] Disperse 60 g of graphene oxide in deionized water and ultrasonically disperse for 30 min to obtain a 100 mg / mL dispersion.

[0110] 60 g of TiC nanocrystals were added to the dispersion and magnetically stirred for 2 h. Ammonia water was then added dropwise until the pH was 9, 2.4 mL of hydrazine hydrate was slowly added, and the mixture was reacted in a water bath at 60 ° C for 12 h. The mixture was then centrifuged at 8000 rpm to remove residual ammonia water and hydrazine hydrate. The separated solid product was washed with deionized water and vacuum dried at 60 ° C for 18 h to obtain graphene / TiC core-shell particles.

[0111] Comparative Example 1

[0112] The difference between this comparative example and Example 1 is that the etching solution used in S2 includes: 35g of 85% phosphoric acid, 10g of 65% nitric acid and 35g of deionized water.

[0113] Comparative Example 2

[0114] This comparative example differs from Example 1 in that the carbon-titanium composite slurry used in S302 includes 100 g of SiO2 / TiC core-shell particles, 12 g of titanate coupling agent NDZ-101, 108 g of phenolic resin, and 36 g of anhydrous ethanol. The manufacturing method includes:

[0115] Titanate coupling agent NDZ-101 was dispersed in anhydrous ethanol and then ultrasonically dispersed for 15 minutes. SiO2 / TiC core-shell particles were added and ball milled for 2 hours (speed 300 rpm). Subsequently, phenolic resin (molecular weight 1000) was added and ball milling was continued for 1 hour to obtain a carbon-titanium composite slurry.

[0116] The preparation method of SiO2 / TiC core-shell particles is as follows:

[0117] 20 g of TiC nanocrystals were dispersed in 200 mL of anhydrous ethanol, and ammonia water was added to adjust the pH to 9. 10 mL of tetraethyl orthosilicate was slowly added dropwise and stirred at 30 ° C for 6 h to allow TEOS (tetraethyl orthosilicate) to hydrolyze to generate SiO2, which evenly coated the TiC surface. After centrifugation, the mixture was washed with ethanol and water respectively, and dried at 60 ° C to obtain SiO2 / TiC composite particles.

[0118] The SiO2 particle size is 5 to 8 nm and the purity is ≥99%.

[0119] The high-capacity carbon-titanium composite electrode foils manufactured in Examples 1 to 6 and Comparative Examples 1 to 2 were tested.

[0120] 1. Electrochemical performance test

[0121] The electrode foils obtained in each embodiment and comparative example were cut into 1 cm × 1 cm samples and pasted on a 1 cm × 1 cm copper sheet with conductive silver glue, while reserving a 1 cm × 0.5 cm copper sheet as the wire connection end. The samples were dried at room temperature for 24 h to obtain working electrodes. The working electrode, reference electrode (Ag / AgCl, saturated KCl solution), and counter electrode (platinum sheet, 1 cm × 1 cm) were vertically immersed in a 1 mol / L H2SO4 electrolyte with an electrode spacing of 1 cm.

[0122] The potential range was set at -0.2 to 0.8 V, the scan rate was 10 mV / s, and the stable value was obtained after 3 cycles. The specific capacitance C was calculated by the integral area of the CV curve:

[0123]

[0124] Where C is the specific capacitance, I is the current, ∫IdV is the integrated area of the cyclic voltammetry curve, v is the scan rate, and ΔV is the potential window.

[0125] 2. Interface bonding strength test

[0126] Using the cross-hatch method, a grid cutter was used to make vertical cross cuts on the surface on one side of the surface layer to form a 10×10 (100 grids) 1mm×1mm grid (the cutting depth penetrated the coating to the aluminum foil substrate); the grid area was tightly adhered with tape (3M600 tape), pressed for 10 seconds, and quickly torn off at a 60° angle. The number of grids that fell off was observed and graded (grade 0: no falling off; grade 5: >65% falling off).

[0127] Tensile test: A 2cm×2cm electrode foil was bonded to a 2cm×2cm aluminum sheet using epoxy adhesive (EPO-TEK353ND, cured at 80°C / 2h) to form a sandwich structure of electrode foil, adhesive layer, and aluminum sheet. Using a universal material testing machine, the structure was stretched at a rate of 5mm / min, and the peel strength (N / cm) was recorded.

[0128]

[0129] The test results are shown in Table 1.

[0130] Table 1

[0131] Group Specific capacitance (F / g) Cross-cutting grade Peel strength (N / cm) Example 1 844 0 18.4 Example 2 671 2 10.6 Example 3 822 0 18.2 Example 4 873 1 16.9 Example 5 724 0 17.5 Example 6 554 3 8.3 Comparative Example 1 582 1 12.3 Comparative Example 2 178 2 6.9

[0132] Combined with Table 1, compared with Example 1, Example 2 has a cross-hatch test grade of 2 (about 15% detachment), that is, in the absence of dopamine bonding, the interface bonding is mainly physical adsorption, so the interface bonding strength is reduced. At the same time, the dopamine + glycyrrhizic acid treatment in Example 1 increases the hydroxyl density on the electrode foil surface, providing strong chemical adsorption sites for the subsequent graphene / TiC.

[0133] The cross-hatch test grade of Example 3 is consistent with that of Example 1, both being grade 0, indicating that cerium oxide does not affect the interfacial bonding strength, but does affect the comparative capacitance, which decreases slightly.

[0134] In Example 4, the increase in the thickness of the carbon-titanium composite slurry leads to an increase in the loading amount of the active material and an increase in the specific capacitance. However, the thicker coating of the carbon-titanium composite slurry leads to an increase in the internal stress and a decrease in the peel strength.

[0135] The porosity of the aluminum foil in Example 5 is lower than that in Example 1, resulting in a decrease in specific surface area and a decrease in specific capacitance. The dopamine + glycyrrhizic acid treatment maintains the interfacial bonding force at a relatively high level (cross-hatch method grade 0).

[0136] Example 6 lacks the dopamine+glycyrrhizic acid treatment, and the interfacial bonding force is significantly reduced. The porosity of the aluminum foil is lower than that of Example 1, and the specific capacitance is reduced.

[0137] The etching solution of Comparative Example 1 lacks chitosan hydrochloric acid solution, and the uneven etching leads to decreased coating adhesion, decreased interfacial bonding force and peel strength. At the same time, the porosity of the aluminum foil decreases compared with Example 1, and the specific capacitance also decreases.

[0138] In Comparative Example 2, the graphene / TiC core-shell particles are replaced with SiO2 / TiC core-shell particles. The SiO2 insulating layer blocks electron transmission, and the specific capacitance drops sharply. At the same time, the interface between SiO2 and phenolic resin is only bonded by van der Waals force, and the peel strength drops significantly.

[0139] The specific capacitance test of the electrode foil obtained in Example 1 was further performed:

[0140] The electrode foil was cut into a 20 cm × 20 cm square and placed in a 70 g / L boric acid solution for 3 minutes. The corrosion holes on one side of the electrode foil were filled with epoxy resin. The single-sided specific capacity was measured in an 80 g / L ammonium pentaborate solution. The formula is:

[0141]

[0142] Where I is the current, Δt is the discharge time, A is the effective area, and ΔV is the potential window.

[0143] The electrode foil obtained in Example 1 was subjected to a high-frequency ESR (equivalent series resistance) test at 100 kHz:

[0144] The electrode foil, polypropylene microporous diaphragm (thickness 12 μm, pore size 0.1 μm), and counter electrode (high-purity aluminum foil, Al ≥ 99%) obtained in Example 1 were stacked in sequence and packaged into a coin-shaped battery cell with a diameter of 20 mm at 5 MPa using a tablet press. 50 μL of electrolyte was injected, and the cell was sealed and allowed to stand for 12 hours to allow the electrolyte to fully infiltrate.

[0145] Connect the fixture to the impedance analyzer and perform an open-short-load calibration (OLC calibration). Set the impedance analyzer parameters to a 100kHz frequency, 10mV AC voltage amplitude, 0V DC bias, and 10 averages. Connect the simulated battery cell to the fixture to ensure good contact. After stabilizing in a 25°C constant temperature box for 5 minutes, measure and record the real resistance (Z′), which is the ESR value.

[0146] The test results are shown in Table 2.

[0147] Table 2

[0148] sample <![CDATA[Specific capacitance (μF / cm 2 )]]> <![CDATA[ESR value (Ω·cm 2 )]]> Example 1 4600 0.003

[0149] Furthermore, the electrode foil manufactured in Example 1 has an impedance phase angle of >-5° at 1 MHz, which is suitable for 5G base station filters; its roll-to-roll speed is 30 m / min, and the yield rate is >99%, which is suitable for mass production.

[0150] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A method for manufacturing a high-capacity carbon-titanium composite electrode foil, characterized in that: It includes the following steps: S1. Pretreatment: Immerse the aluminum foil in a mixture of 10% sulfuric acid and 0.5% hydrofluoric acid for 30 seconds and then remove it to complete the pretreatment step; S2. Micro-etching: The etching solution is heated to 45-55°C and micro-etched using the etching solution under ultrasonic conditions to form micropores with a pore size of 0.5-2 μm on the aluminum foil. After etching, the aluminum foil is washed with deionized water and dried at 80°C to obtain micro-etched aluminum foil. The etching time is 8-12 minutes and the spray pressure is 2-3 kg / cm 2 ; S3. Construction of carbon-titanium active layer: S301, bottom layer construction: After etching the micro-etched aluminum foil with argon plasma for 5 minutes, argon and methane were introduced to sputter TiC nanocrystals onto the surface of the micro-etched aluminum foil to obtain a TiC nanocrystal bottom layer, thus completing the bottom layer construction; S302, middle layer construction: The carbon-titanium composite slurry was coated on the TiC nanocrystalline bottom layer, vacuum dried at 80°C for 12 hours, then cured at 300°C in a nitrogen atmosphere for 1 hour, then kept at 500°C in an Ar / H2 / NH3 mixture for 2 hours, and then kept at 600°C in a vacuum environment for 1 hour. After cooling, the intermediate layer was constructed. The carbon-titanium composite slurry coating thickness was 12 to 60 μm. S303, surface construction: The electrode foil after the intermediate layer construction obtained in S302 is immersed in the coating sol, coated by dip coating, dried at room temperature for 30 minutes, and then dried at 60°C for 1 hour. Subsequently, the temperature is raised to 300°C in a tube furnace, kept warm for 1 hour under a nitrogen atmosphere, and then continued to be raised to 600°C, kept warm for 2 hours in an argon atmosphere, and cooled to room temperature to complete the surface layer construction, thereby obtaining a high-capacity carbon-titanium composite electrode foil, wherein the coating thickness is 5 to 10 μm; The coating sol comprises tetrabutyl titanate, glucose, urea and ethanol, wherein the mass volume ratio of the tetrabutyl titanate, glucose, urea and ethanol is 1 g:2 g:3 g:10 mL. The manufacturing method of the coating sol comprises: Glucose, urea and ethanol were mixed and stirred to dissolve, and tetrabutyl titanate was added dropwise. The mixture was stirred for 30 minutes to obtain a coating sol.

2. The method for manufacturing a high-capacity carbon-titanium composite electrode foil according to claim 1, wherein: After S303, it further includes: S4. Post-treatment: spraying cerium oxide sol on the surface layer and drying it at 60° C. for 20 minutes to complete the post-treatment. The spraying thickness of the cerium oxide sol is 100 nm.

3. The method for manufacturing a high-capacity carbon-titanium composite electrode foil according to claim 2, wherein: The cerium oxide sol preparation method comprises the following steps: After dissolving cerium nitrate hexahydrate in deionized water, the pH value was adjusted to 9-10 with ammonia water, and the cerium oxide sol was obtained after aging for 24 hours.

4. The method for manufacturing a high-capacity carbon-titanium composite electrode foil according to claim 1, wherein: The etching solution comprises 30-40 parts of 85% phosphoric acid, 8-15 parts of 65% nitric acid, 1 part of hydroxyethyl cellulose, 20-30 parts of 1% chitosan hydrochloric acid solution, and 30-40 parts of deionized water.

5. The method for manufacturing a high-capacity carbon-titanium composite electrode foil according to claim 1, wherein: In S302, the carbon-titanium composite slurry includes graphene / TiC core-shell particles, a titanate coupling agent, a phenolic resin, and anhydrous ethanol in a mass ratio of (8-9):1:9:3, and the manufacturing method thereof includes: After dispersing the titanate coupling agent in anhydrous ethanol, the graphene / TiC core-shell particles were added and ball-milled for 2 h. Subsequently, the phenolic resin was added and ball-milled for 1 h to obtain a carbon-titanium composite slurry.

6. The method for manufacturing a high-capacity carbon-titanium composite electrode foil according to claim 5, wherein: The method for manufacturing the graphene / TiC core-shell particles comprises: Graphene oxide was dispersed in deionized water and ultrasonically dispersed for 30 min to obtain a 100 mg / mL dispersion. TiC nanocrystals were added to the dispersion and magnetically stirred for 2 hours. Ammonia water was then added dropwise until the pH was 9. Hydrazine hydrate was added and the mixture was reacted in a water bath at 60°C for 12 hours. The mixture was then centrifuged. The separated solid product was washed with deionized water and vacuum dried at 60°C for 18 hours to obtain graphene / TiC core-shell particles. The mass ratio of the TiC nanocrystals to the graphene oxide was 1:1, and the mass-to-volume ratio of the graphene oxide to the hydrazine hydrate was 25 g:1 mL.

7. The method for manufacturing a high-capacity carbon-titanium composite electrode foil according to claim 1, wherein: After S2 and before S3, the process further includes the following steps: The micro-etched aluminum foil was immersed in the dopamine solution and oscillated at room temperature for 2 h. It was then rinsed with deionized water and dried. It was then immersed in the glycyrrhizic acid solution for 5 min and then taken out and dried at 80°C.

8. The method for manufacturing a high-capacity carbon-titanium composite electrode foil according to claim 7, wherein: The dopamine solution has a concentration of 2 mg / mL. The method for preparing the dopamine solution comprises the following steps: dissolving dopamine hydrochloride in a Tris-HCl buffer to obtain a dopamine solution, wherein the Tris-HCl buffer has a pH of 8.5 and a concentration of 10 mmol / L.

9. The method for manufacturing a high-capacity carbon-titanium composite electrode foil according to claim 1, wherein: The aluminum foil is 1050 aluminum foil, 1070 aluminum foil or 1090 aluminum foil with a thickness of 20 to 30 μm.

10. A high-capacity carbon-titanium composite electrode foil, characterized in that: The high-capacity carbon-titanium composite electrode foil is manufactured by the manufacturing method of any one of claims 1 to 9.

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