A high capacity carbon-titanium composite electrode foil and a method of manufacturing the same

Abstract

The application 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: after the aluminum foil is immersed in a mixed solution of 10% sulfuric acid and 0.5% hydrofluoric acid for 30s, the pretreatment step is completed; S2, micro-etching: the etching solution is heated to 45-55 DEG C, and the micro-etching is carried out under ultrasonic waves by using the etching solution, so that micropores with a pore diameter of 0.5-2 mu m are formed on the aluminum foil; after the etching is completed, the deionized water is used for washing, and the aluminum foil is dried at 80 DEG C, thereby obtaining the micro-etched aluminum foil; and S3, carbon-titanium active layer construction. The application provides a high-capacity carbon-titanium composite electrode foil and a manufacturing method thereof, so as to solve the problems that the thermal expansion coefficient difference between titanium and carbon material is large in the related art, the interface stress is easily concentrated, and the porous structure formed by micro-etching is easily cracked under the cyclic stress.

Description

TECHNICAL FIELD

[0001] The present application 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. BACKGROUND

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

[0003] In related technologies, methods usually include forming a microporous structure on the surface of the aluminum foil by chemical or electrochemical etching to expand the specific surface area, and improving the dielectric performance by coating titanium oxide on the surface of the aluminum foil. However, the former is prone to mechanical performance degradation of the aluminum foil when the micropore is more than 50 μm, leading to cracking of the electrode in the charge and discharge cycle, and the inner wall of the micropore lacks active sites, resulting in poor electrolyte wettability and limiting ion transport efficiency. In the latter method, although titanium dioxide has a high dielectric constant, titanium dioxide is prone to hydration reaction in acidic electrolyte, resulting in capacity attenuation, and the physical adsorption coating has the risk of falling off in the cycle.

[0004] For the above problems, in recent years, the research on carbon-titanium composite electrode foil has made significant progress through microstructure regulation and interface optimization. The titanium-carbon gradient layer has high dielectric performance (TiO2) and high electrical conductivity (carbon), which can achieve fast charge migration at high frequency, and the mass specific capacity in supercapacitors can reach 600 F / g, which is more than 3 times higher than that of pure aluminum foil, and can still maintain a relatively stable capacity after multiple cycles, which is much better than the traditional TiO2 coating. However, the thermal expansion coefficients of titanium and carbon materials are quite different (titanium: 8.6 x 10 -6 / ℃, carbon: 2.2 x 10 -6 / ℃), which easily leads to interface stress concentration, and the porous structure formed by micro-etching is prone to cracking of the titanium substrate under cyclic stress. SUMMARY

[0005] The present application provides a high-capacity carbon-titanium composite electrode foil and a manufacturing method thereof to solve the problem that the thermal expansion coefficients of titanium and carbon materials are quite different in related technologies, which easily leads to interface stress concentration, and the porous structure formed by micro-etching is prone to cracking of the titanium substrate under cyclic stress.

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

[0007] S1, pretreatment: the aluminum foil is immersed in a mixture of 10% sulfuric acid and 0.5% hydrofluoric acid for 30s, and then taken out, to complete the pretreatment step;

[0008] S2, micro-etching: the etching solution is heated to 45-55°C, and micro-etching is performed under ultrasonic wave using the etching solution to form micropores with a pore size of 0.5-2μm on the aluminum foil, after the etching is completed, deionized water is used for washing, and drying is performed at 80°C, to obtain a micro-etched aluminum foil, the etching time is 8-12min, and the spraying pressure is 2-3kg / cm 2 ;

[0009] S3, carbon-titanium active layer construction:

[0010] S301, bottom layer construction:

[0011] After the micro-etched aluminum foil is etched using argon plasma for 5min, argon and methane are introduced, and TiC nanocrystals are sputtered to 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 is coated on the TiC nanocrystal bottom layer, vacuum drying is performed at 80°C for 12h, then curing is performed at 300°C in a nitrogen atmosphere for 1h, then heat preservation is performed at 500°C in Ar / H2 / NH3 mixed gas for 2h, and then heat preservation is performed at 600°C in a vacuum environment for 1h, after cooling, the middle layer construction is completed, and the coating thickness of the carbon-titanium composite slurry is 12-60μm;

[0014] S303, surface layer construction:

[0015] The electrode foil after the middle layer construction obtained in S302 is immersed in a coating sol, coating is performed using a dip coating method, air drying is performed at room temperature for 30min, drying is performed at 60°C for 1h, then the temperature is increased to 300°C in a tube furnace, heat preservation is performed at 300°C in a nitrogen atmosphere for 1h, the temperature is continuously increased to 600°C, heat preservation is performed at 600°C in an argon atmosphere for 2h, and after cooling to room temperature, the surface layer construction is completed, to obtain a high-capacity carbon-titanium composite electrode foil, wherein the coating thickness is 5-10μm;

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

[0017] After the glucose, urea, and ethanol are mixed and stirred to be dissolved, the tetrabutyl titanate is added dropwise, and the coating sol is obtained after continuous stirring for 30min.

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

[0019] S4, post-processing: spray cerium oxide sol on the surface layer, and dry at 60℃ for 20min to complete the post-processing, the cerium oxide sol spray thickness is 100nm.

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

[0021] After dissolving cerium nitrate hexahydrate in deionized water, use ammonia to adjust the pH to 9-10, and then age for 24h to obtain cerium oxide sol.

[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 hydrochloride solution, and 30-40 parts of deionized water.

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

[0024] After dispersing the titanate coupling agent in anhydrous ethanol, add graphene / TiC core-shell particles, ball mill and mix for 2h, then add phenolic resin and continue to ball mill for 1h to obtain the carbon-titanium composite slurry.

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

[0026] Disperse graphene oxide into deionized water, ultrasonic dispersion for 30min to obtain a dispersion liquid of 100mg / mL;

[0027] Add TiC nanocrystals into the dispersion liquid, magnetic stirring for 2h, then add ammonia water dropwise to pH 9, add hydrazine hydrate, react at 60℃ water bath for 12h, then centrifuge, wash the separated solid product with deionized water, and vacuum dry at 60℃ for 18h to obtain graphene / TiC core-shell particles, the mass ratio of TiC nanocrystals to graphene oxide is 1:1, and the mass-volume ratio of graphene oxide to hydrazine hydrate is 25g:1mL.

[0028] Preferably, after S2 and before S3, it further comprises the following steps:

[0029] Immerse the micro-etched aluminum foil into the dopamine solution, oscillate at room temperature for 2h, then wash with deionized water and dry, then immerse in glycyrrhizic acid solution for 5min, and then take out and dry at 80℃.

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

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

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

[0033] The technical solutions provided in the present application have the following beneficial effects:

[0034] The present application provides a high-capacity carbon-titanium composite electrode foil and a manufacturing method thereof. The high-capacity carbon-titanium composite electrode foil is manufactured by constructing a high-roughness substrate through surface etching, increasing the specific surface area, and retaining the tensile strength. Then, a TiC nanocrystalline bottom layer, a carbon-titanium composite intermediate layer, and a surface layer are formed by magnetron sputtering. 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 are generated by a reduction carbonization reaction at high temperature to generate TiC, and N is doped into the crystal lattice through a substitution or interstitial mechanism to form N-TiC. During the sol-gel process, titanium hydroxyl groups form chemical bonds (Ti-O-Al) with aluminum foil surface hydroxyl groups (exposed after etching), and the carbon network mechanically interlocks with the aluminum foil after carbonization, thereby improving the adhesion of the coating. Therefore, the problems of a large difference in the thermal expansion coefficient between titanium and carbon materials, which easily leads to interface stress concentration, and the porous structure formed by micro-etching, which easily causes the titanium substrate to crack under cyclic stress, can be solved. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0036] Figure 1 A flowchart of the manufacturing method of the high-capacity carbon-titanium composite electrode foil provided in the present application is shown in the following figure.

[0037] Figure 2 A specific flowchart of S3 in the manufacturing method of the high-capacity carbon-titanium composite electrode foil provided in the present application is shown in the following figure. DETAILED DESCRIPTION

[0038] To make the purposes, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work belong to the scope of protection of the present application.

[0039] Referring to Figures 1-2 As shown in the drawings, 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 by the present application, the aluminum foil used is Al≥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 manufacturing method of the high-capacity carbon-titanium composite electrode foil includes the following steps:

[0044] S1, pretreatment: immerse the 1070 aluminum foil with a thickness of 25 μm in a mixed solution of 10% sulfuric acid and 0.5% hydrofluoric acid for 30 s, take it out after removing the oxide layer, and complete the pretreatment step;

[0045] S2, micro-etching: heat the etching solution to 50°C, use the etching solution to perform micro-etching under ultrasonic wave, form micropores with a pore size of 1 μm (aspect ratio 3:1) on the aluminum foil, after etching, wash with deionized water, and dry at 80°C, to obtain a micro-etched aluminum foil, etching time is 10 min, and the spraying pressure is 2.5 kg / cm 2 ;

[0046] Immerse the micro-etched aluminum foil in a 2 mg / mL dopamine solution, shake at room temperature for 2 h, rinse with deionized water and dry, then immerse in a glycyrrhizic acid solution for 5 min, take it out, and dry at 80°C.

[0047] S3, carbon-titanium active layer construction:

[0048] S301, bottom layer construction:

[0049] After etching the micro-etched aluminum foil with argon plasma for 5 min, argon and methane are 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] The carbon-titanium composite slurry is coated on the TiC nanocrystalline bottom layer using a coater, vacuum dried at 80°C for 12h, then cured at 300°C in a nitrogen atmosphere for 1h, then heat treated at 500°C for 2h in an Ar / H2 / NH3 mixed gas (Ar:H2:NH3=6:3:1), and then heat treated at 600°C for 1h in a vacuum environment, to complete the construction of the intermediate layer after cooling. The coating thickness of the carbon-titanium composite slurry is 40μm, and the dry film thickness (thickness after drying of the carbon-titanium composite slurry) is 8μm.

[0052] S303, surface layer construction:

[0053] The electrode foil after the construction of the intermediate layer obtained in S302 is immersed in the coating sol, and coating is performed using dip coating. After air drying at room temperature for 30min, drying is performed at 60°C for 1h. Then, the temperature is raised to 300°C in a tube furnace, and heat treatment is performed at 300°C in a nitrogen atmosphere for 1h. The temperature is continuously raised to 600°C, and heat treatment is performed at 600°C in an argon atmosphere for 2h. After cooling to room temperature, the surface layer construction is completed, and a high-capacity carbon-titanium composite electrode foil is obtained. The coating thickness is 8μm.

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

[0055] After mixing and stirring to dissolve the glucose, urea, and ethanol, tetrabutyl titanate is added dropwise. After continuing to stir for 30min, the coating sol is obtained.

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

[0057] After dissolving cerium nitrate hexahydrate in deionized water, the pH is adjusted to 9 using ammonia water. After aging for 24h, the cerium oxide sol is obtained.

[0058] The etching solution used in S2 includes 35g of 85% concentrated phosphoric acid, 10g of 65% concentrated nitric acid, 1g of hydroxyethyl cellulose, 25g of 1% chitosan hydrochloride solution (0.4g of chitosan, 0.2g of hydrochloric acid, and the balance being 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. The manufacturing method includes the following steps:

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

[0061] The graphene / TiC core-shell particles were prepared by the following method:

[0062] 60 g of graphene oxide was dispersed in deionized water and ultrasonically dispersed for 30 min to obtain a dispersion liquid of 100 mg / mL;

[0063] 60 g of TiC nanocrystals were added to the dispersion liquid and magnetically stirred for 2 h, then ammonia water was added dropwise to pH 9, 2.4 mL of hydrazine hydrate was slowly added, and after reaction at 60°C water bath for 12 h, centrifugation was carried out at a rotation speed of 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 solution to obtain a dopamine solution, wherein the Tris-HCl buffer solution had a pH of 8.5 and a concentration of 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] The manufacturing method of the high-capacity carbon-titanium composite electrode foil provided in this embodiment is consistent with that of Example 1, except that the dopamine solution and the glycyrrhizic acid solution are not immersed 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 of Example 1, except that the 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 of Example 1, except that the carbon-titanium composite slurry coating thickness is 60 μm and the dry film thickness (thickness after drying of the carbon-titanium composite slurry) is 12 μm in step S302.

[0072] Example 5

[0073] The manufacturing method of the high-capacity carbon-titanium composite electrode foil provided in this embodiment includes the following steps:

[0074] S1, pretreatment: immerse 1050 aluminum foil with a thickness of 20 pm in a mixture of 10% sulfuric acid and 0.5% hydrofluoric acid for 30 s, remove after removing the oxide layer, and complete the pretreatment step;

[0075] S2, micro-etching: heat the etching solution to 45°C, and use the etching solution to perform micro-etching under ultrasonic waves to form micropores with a pore size of 0.5-1 pm (aspect ratio 3:1) on the aluminum foil, after etching, wash with deionized water, and dry at 80°C to obtain a micro-etched aluminum foil, etching time 8 min, spray pressure 2 kg / cm 2 ;

[0076] Immerse the micro-etched aluminum foil in a 2 mg / mL dopamine solution, shake at room temperature for 2 h, rinse with deionized water and dry, then immerse in a glycyrrhizic acid solution for 5 min, remove, and dry at 80°C.

[0077] S3, carbon-titanium active layer construction:

[0078] S301, bottom layer construction:

[0079] After etching the micro-etched aluminum foil with argon plasma for 5 min, introduce argon and methane, and 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] Use a coater to coat the carbon-titanium composite slurry onto the TiC nanocrystal bottom layer, vacuum dry at 80°C for 12 h, then cure at 300°C in a nitrogen atmosphere for 1 h, then heat at 500°C in a mixed gas of Ar / H2 / NH3 (Ar:H2:NH3=6:3:1) for 2 h, and then heat at 600°C in a vacuum environment for 1 h, after cooling, complete the middle layer construction, the coating thickness of the carbon-titanium composite slurry is 12 pm, and the dry film thickness (thickness after drying of the carbon-titanium composite slurry) is 3 pm;

[0082] S303, surface layer construction:

[0083] Immerse the electrode foil after completing the middle layer construction obtained in S302 into the coating sol, use dip coating method for coating, air dry at room temperature for 30 min, then dry at 60°C for 1 h, then heat to 300°C in a tube furnace, heat at 300°C in a nitrogen atmosphere for 1 h, continue to heat to 600°C, heat at 600°C in an argon atmosphere for 2 h, and cool to room temperature to complete the surface layer construction, to obtain a high-capacity carbon-titanium composite electrode foil, wherein the coating thickness is 10 pm;

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

[0085] After mixing and stirring to dissolve the glucose, urea and ethanol, tetrabutyl titanate was added dropwise, and after stirring for 30 min, a coating sol was obtained.

[0086] S4, post-treatment: cerium oxide sol was sprayed on the surface layer, and after drying at 60°C for 20 min, the post-treatment was completed. The thickness of the cerium oxide sol sprayed was 100 nm. The method for preparing the cerium oxide sol included the following steps:

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

[0088] The etching solution used in S2 included 30 g of 85% concentrated phosphoric acid, 8 g of 65% concentrated nitric acid, 1 g of hydroxyethyl cellulose, 20 g of 1% chitosan hydrochloride solution (0.2 g of chitosan, 0.1 g of hydrochloric acid, and the balance being deionized water), and 30 g of deionized water.

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

[0090] After dispersing the titanate coupling agent in anhydrous ethanol and ultrasonic dispersion for 15 min, the graphene / TiC core-shell particles were added, and ball milling was performed for 2 h (rotation speed 300 rpm). Subsequently, the phenolic resin (molecular weight 1000) was added, and ball milling was continued for 1 h to obtain a carbon-titanium composite slurry.

[0091] The method for preparing the graphene / TiC core-shell particles, and the methods for preparing the dopamine solution and the glycyrrhizic acid solution were consistent with those of Example 1.

[0092] Example 6

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

[0094] S1, pretreatment: 1090 aluminum foil with a thickness of 30 μm was immersed in a mixture of 10% sulfuric acid and 0.5% hydrofluoric acid for 30 s, and after removing the oxide layer, it was taken out to complete the pretreatment step.

[0095] S2, micro-etching: the etching solution was heated to 55°C, and micro-etching was performed using the etching solution under ultrasonic waves to form micropores with a pore size of 1-2 μm (depth-width ratio 3:1) on the aluminum foil. After etching, deionized water was used for washing, and drying was performed at 80°C. The etching time was 12 min, and the spray pressure was 3 kg / cm 2 ;

[0096] S3, carbon-titanium active layer construction:

[0097] S301, bottom layer construction:

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

[0099] S302, intermediate layer construction:

[0100] The carbon-titanium composite slurry is coated onto the TiC nanocrystal bottom layer using a coater, vacuum dried at 80°C for 12h, then cured at 300°C in a nitrogen atmosphere for 1h, then heat treated at 500°C for 2h in a mixed gas of Ar / H2 / NH3(Ar:H2:NH3=6:3:1), and then heat treated at 600°C for 1h in a vacuum environment. After cooling, the intermediate layer construction is completed, the carbon-titanium composite slurry coating thickness is 40μm, and the dry film thickness (thickness after drying of the carbon-titanium composite slurry) is 8μm;

[0101] S303, surface layer construction:

[0102] The electrode foil after the intermediate layer construction obtained in S302 is immersed in the coating sol, coated using dip coating, air dried at room temperature for 30min, dried at 60°C for 1h, then heated to 300°C in a tube furnace, heat treated at 300°C in a nitrogen atmosphere for 1h, continuously heated to 600°C, heat treated at 600°C in an argon atmosphere for 2h, and cooled to room temperature to complete the surface layer construction. A high-capacity carbon-titanium composite electrode foil is obtained, wherein the coating thickness is 8μm;

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

[0104] After mixing and stirring to dissolve the glucose, urea, and ethanol, tetrabutyl titanate is added dropwise, and the coating sol is obtained after continuing to stir for 30min.

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

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

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

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

[0109] 60 g of graphene oxide was dispersed in deionized water and ultrasonically dispersed for 30 min to obtain a dispersion liquid of 100 mg / mL;

[0110] 60 g of TiC nanocrystals were added to the dispersion liquid and magnetically stirred for 2 h, then ammonia water was added dropwise to pH 9, 2.4 mL of hydrazine hydrate was slowly added, and after reaction at 60°C water bath for 12 h, centrifugation was carried out at a rotation speed of 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 35 g of phosphoric acid with a concentration of 85%, 10 g of nitric acid with a concentration of 65%, and 35 g of deionized water.

[0113] Comparative Example 2

[0114] The difference between this comparative example and Example 1 is that the manufacturing method of 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, and the manufacturing method includes:

[0115] The titanate coupling agent NDZ-101 was dispersed in anhydrous ethanol and ultrasonically dispersed for 15 min, then the SiO2 / TiC core-shell particles were added, and ball-milling mixed for 2 h (rotation speed 300 rpm), then the phenolic resin (molecular weight 1000) was added, and ball-milling was continued for 1 h to obtain a carbon-titanium composite slurry.

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

[0117] 20 g of TiC nanocrystals were dispersed in 200 mL of anhydrous ethanol, ammonia water was added to adjust the pH to 9, 10 mL of tetraethyl orthosilicate was slowly added dropwise, and stirring was carried out at 30°C for 6 h to make TEOS (tetraethyl orthosilicate) hydrolyze to form SiO2 and uniformly coat the surface of TiC; after centrifugation, ethanol and water were used for washing, and after drying at 60°C, SiO2 / TiC composite particles were obtained.

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

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

[0120] I. Electrochemical performance test

[0121] The electrode foils produced in each example and comparative example were cut into 1 cm x 1 cm samples, which were adhered to 1 cm x 1 cm copper sheets using conductive silver paste, with 1 cm x 0.5 cm copper sheets reserved as wire connection ends. The working electrodes were dried at room temperature for 24 h, and then obtained. The working electrode, reference electrode (Ag / AgCl, saturated KCl solution), and counter electrode (platinum sheet, 1 cm x 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 to -0.2-0.8 V, the scan rate was 10 mV / s, and the stable value was taken after 3 cycles. The specific capacitance C was calculated by integrating the 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] II. Interface bonding force test

[0126] A grid method was used, in which a hundred-grid knife was used to vertically intersect the surface on which the surface layer was located, forming a 10 x 10 (100 grid) 1 mm x 1 mm grid (the cutting depth penetrated the coating to the aluminum foil substrate). The grid area was tightly adhered with tape (3M600 tape), and was quickly peeled off at an angle of 60° after pressing for 10 s. The number of detached grids was observed and graded (0 grade: no detachment; 5 grade: >65% detachment).

[0127] Tensile test: A 2 cm x 2 cm electrode foil and a 2 cm x 2 cm aluminum sheet were bonded using epoxy glue (EPO-TEK353ND, curing conditions: 80°C / 2 h), forming a "sandwich" structure of "electrode foil-glue layer-aluminum sheet". A universal material testing machine was used to stretch at a rate of 5 mm / 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) Grid method rating (level) Peeling 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] In combination with Table 1, the crosshatch rating of Example 2 is grade 2 (about 15% peeling), that is, in the absence of dopamine bonding, the interface bonding is mainly physical adsorption, so the interface bonding force decreases; at the same time, the dopamine + licorice acid treatment in Example 1 increases the surface hydroxyl density of the electrode foil, providing strong chemical adsorption sites for subsequent graphene / TiC.

[0133] The crosshatch rating of Example 3 remains consistent with Example 1, both being grade 0, indicating that cerium oxide does not affect the interface bonding force, but has an impact on the specific 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 of active materials, and the specific capacitance increases, but the thickening of the carbon-titanium composite slurry leads to an increase in internal stress, and the peeling strength decreases.

[0135] In Example 5, the porosity of the aluminum foil decreases compared to Example 1, resulting in a decrease in specific surface area and specific capacitance, and the dopamine + licorice acid treatment maintains a high level of interface bonding force (crosshatch rating grade 0).

[0136] In Example 6, the absence of dopamine + licorice acid treatment significantly reduces the interface bonding force, and the porosity of the aluminum foil decreases compared to Example 1, resulting in a decrease in specific capacitance.

[0137] In Comparative Example 1, the etching solution lacks chitosan hydrochloride solution, resulting in uneven etching and a decrease in coating adhesion, interface bonding force, and peeling strength, and the porosity of the aluminum foil decreases compared to Example 1, resulting in a decrease in specific capacitance.

[0138] In Comparative Example 2, the graphene / TiC core-shell particles are replaced with SiO2 / TiC core-shell particles, and the SiO2 insulating layer blocks electron transport, resulting in a sharp decrease in specific capacitance, and the interface between SiO2 and phenolic resin is only bonded by van der Waals force, resulting in a significant decrease in peeling strength.

[0139] Further specific capacity tests were conducted on the electrode foil obtained in Example 1:

[0140] The electrode foil was cut into a square of 20 cm x 20 cm, and after being stabilized in a 70 g / L boric acid solution for 3 min, the etched 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, and 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 high-frequency ESR (equivalent series resistance) testing at 100 kHz:

[0144] The electrode foil manufactured in Example 1, a polypropylene microporous separator (thickness 12 pm, pore size 0.1 pm), and a counter electrode (high-purity aluminum foil, Al > 99%) were sequentially stacked, and a coin-type battery with a diameter of 20 mm was packaged using a tablet press at 5 MPa, 50 pL of electrolyte was injected, and after sealing, the electrolyte was allowed to fully soak for 12 h.

[0145] The connecting clamp was connected to the impedance analyzer, and an "open-short-load" calibration (OLC calibration) was performed; the impedance analyzer parameter facility was set to a frequency of 100 kHz, an alternating voltage amplitude of 10 mV, a direct current bias of 0 V, and an average number of 10 times; the analog battery was connected to the clamp, good contact was ensured, and after being stabilized in a 25°C constant-temperature box for 5 minutes, the real part resistance (Z') was measured and recorded, which was the ESR value.

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

[0147] Table 2

[0148] Sample Specific capacitance (pF / cm 2 )]]> ESR value (Ω-cm 2 )]]> Example 1 4600 0.003

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

[0150] The above description is merely a specific implementation of the present application, which enables a person skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

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, then remove it to complete the pretreatment step. S2. Micro-etching: The etching solution is heated to 45–55°C and micro-etched under ultrasonic conditions to form micropores with a diameter of 0.5–2 μm on the aluminum foil. After etching, the foil is washed with deionized water and dried at 80°C to obtain the micro-etched aluminum foil. The etching time is 8–12 minutes, and the spray pressure is 2–3 kg / cm². 2 ; S3, Construction of the carbon-titanium active layer: S301, Underlying Structure: 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 the TiC nanocrystal bottom layer, thus completing the bottom layer construction. S302, Intermediate Layer Construction: The carbon-titanium composite slurry was coated onto the TiC nanocrystalline substrate, dried under vacuum at 80℃ for 12h, then cured at 300℃ under nitrogen atmosphere for 1h, then kept at 500℃ for 2h in Ar / H2 / NH3 mixed gas, and then kept under vacuum at 600℃ for 1h. After cooling, the intermediate layer was completed. The coating thickness of the carbon-titanium composite slurry was 12-60μm. S303, Surface Construction: The electrode foil obtained from S302 after the intermediate layer construction was immersed in the coating sol and coated by dip coating. It was then dried at room temperature for 30 min, and then dried at 60℃ for 1 h. Subsequently, it was heated to 300℃ in a tube furnace and held at this temperature for 1 h under a nitrogen atmosphere. The temperature was then further increased to 600℃ and held at this temperature for 2 h under an argon atmosphere. After cooling to room temperature, the surface layer construction was completed, and a high-capacity carbon-titanium composite electrode foil with a coating thickness of 5–10 μm was obtained. The coating sol comprises tetrabutyl titanate, glucose, urea, and ethanol, wherein the mass-to-volume ratio of tetrabutyl titanate, glucose, urea, and ethanol is 1g:2g:3g:10mL, and the method for manufacturing the coating sol includes: After mixing and dissolving glucose, urea and ethanol, tetrabutyl titanate was added dropwise, and stirring was continued for 30 minutes to obtain the coating sol.

2. The method for manufacturing the high-capacity carbon-titanium composite electrode foil as described in claim 1, characterized in that, Following S303, it also includes: S4. Post-treatment: Cerium oxide sol is sprayed onto the surface layer and dried at 60°C for 20 minutes for post-treatment. The thickness of the cerium oxide sol spray is 100 nm.

3. The method for manufacturing high-capacity carbon-titanium composite electrode foil as described in claim 2, characterized in that: The method for manufacturing cerium oxide sol includes the following steps: Cerium nitrate hexahydrate was dissolved in deionized water, and the pH was adjusted to 9-10 with ammonia. After aging for 24 hours, cerium oxide sol was obtained.

4. The method for manufacturing the high-capacity carbon-titanium composite electrode foil as described in claim 1, characterized in that: 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 the high-capacity carbon-titanium composite electrode foil as described in claim 1, characterized in that: In S302, the carbon-titanium composite slurry comprises graphene / TiC core-shell particles, titanate coupling agent, phenolic resin, and anhydrous ethanol in a mass ratio of (8-9):1:9:3, and its manufacturing method includes: After dispersing the titanate coupling agent in anhydrous ethanol, graphene / TiC core-shell particles were added and ball-milled for 2 hours. Then, phenolic resin was added and ball-milled for another hour to obtain a carbon-titanium composite slurry.

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

7. The method for manufacturing the high-capacity carbon-titanium composite electrode foil as described in claim 1, characterized in that: The process after S2 and before S3 also includes the following steps: The micro-etched aluminum foil was immersed in a dopamine solution and reacted with shaking at room temperature for 2 hours. After rinsing with deionized water and drying, it was immersed in glycyrrhizic acid solution for 5 minutes and then removed and dried at 80°C.

8. The method for manufacturing the high-capacity carbon-titanium composite electrode foil as described in claim 7, characterized in that: The concentration of the dopamine solution is 2 mg / mL. The method for manufacturing the dopamine solution includes 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.

9. The method for manufacturing the high-capacity carbon-titanium composite electrode foil as described in claim 1, characterized in that: The aluminum foil is a 1050, 1070, or 1090 aluminum foil with a thickness of 20–30 μm.

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

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