KR20140136217A - A method of current collector with cubic pattern by photolithography and a capacitor using thereof - Google Patents

Abstract

The present invention relates to a method for manufacturing an aluminum current collector having a cubic pattern structure by using photolithography and an ultra-high-capacity capacitor comprising the same, and more specifically, to a method for widening an area by designing regular patterns on the surface of an aluminum current collector using photolithography and selectively etching the same for forming a cubic pattern structure on the surface of the aluminum current collector, and to an ultra-high-capacity capacitor formed by applying the aluminum current collector having the cubic pattern structure by using photolithography.

Description

[0001] The present invention relates to a method of coating a surface of an aluminum current collector having a three-dimensional pattern structure using photolithography,

The present invention relates to a method of manufacturing an aluminum current collector having a three-dimensional pattern structure by photolithography, and more particularly, To a method of forming a three-dimensional pattern structure on the aluminum collector surface by selectively etching them after a predetermined pattern is formed, and then coating a conductive material with a predetermined thickness on the surface of the current collector.

Due to rising oil prices and global warming, technology in the field of alternative energy has attracted attention, among which energy storage technology has been rapidly developed with the lead of lithium ion secondary battery. However, supercapacitor is used as an alternative to rechargeable secondary battery which is limited in use in fields requiring high output due to its high electric capacity. However, a supercapacitor having a high output capacity is a technology study Gradually expanding the application range to the secondary battery region. In particular, compared to secondary batteries, which are difficult to utilize regenerative braking energy, ultra-high capacity capacitors can utilize regenerative braking energy easily and are being applied to a wider range of fields.

The ultra-high-capacity capacitors are charged and discharged repeatedly by using physical adsorption and desorption reactions of ions in the electrolyte using activated carbon having a large surface area. The role of aluminum, which has a surface area limit in conventional electrolytic capacitors, This substitution made it possible to dramatically improve the electrical capacity. In recent years, concepts such as ultra-high-capacity capacitors using a metal oxide or a carbon nanotube (CNT), a carbon nanofiber (CNF), a composite metal oxide or the like instead of activated carbon have appeared, .

The aluminum foil in the supercapacitor plays a role as a current collector to induce the electrons transferred from the activated carbon to the external circuit and to minimize the resistance generated when electrons are transferred from the activated carbon to the current collector Are required. For this purpose, it is possible to reduce the equivalent series resistance (ESR) of an ultra high capacity capacitor by increasing the contact area with the active material through etching of the surface of the current collector by an electrochemical method. Also, the surface area is much larger than aluminum, Researches have been carried out to improve the contact area between the active material and the current collector by applying a nickel foil as a current collector to lower the ESR of the ultra-high-capacity capacitor and increase the effective capacity. However, Commercialization of the applied ultra-high capacity capacitor has practical problems.

The conventional method for increasing the electric capacity of a supercapacitor is to replace the active material with a metal oxide which performs an oxidation-reduction reaction instead of the activated carbon which performs a physical adsorption and desorption reaction, or a carbon nanotube (CNT ), And the like. This method of replacing the active material has a problem that the first alternative active material is not produced in a large amount or that some production is made, the process equipment manufactured using the existing activated carbon can not be used as it is, and the price of the active material itself It is very expensive and has many problems in terms of cost.

       In order to increase the contact area between the active material and the aluminum current collector so that the effective capacity of the ultra-high capacity capacitor can be increased only by the electrochemical etching method of the aluminum current collector which is currently performed using the electrolytic solution, It has a problem that can not be done.

In order to solve the above problems, the applicant of the present invention has disclosed a manufacturing method of aluminum having a three-dimensional pattern structure by using photolithography in Japanese Patent No. 10-1166148, but it is necessary to further secure corrosion resistance and durability.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art described above by forming a pattern on a surface of a conventional aluminum collector using photolithography and selectively etching the aluminum collector, And an active material coated on the surface of the active material to prevent a direct reaction between the electrolytic solution and aluminum, thereby increasing corrosion resistance and durability.

In order to achieve the above object of the present invention,

Washing the aluminum foil collector and drying it with nitrogen (S1);

(S2) applying a photosensitive liquid onto the surface of the dried aluminum foil current collector and then drying to selectively expose and cure the photosensitive liquid;

After the step S2, the developer is sprayed on the exposed aluminum current collector to selectively remove the unexposed photoresist, and then the remaining photoresist is completely cured to complete the pattern formation on the aluminum current collector (S3);

(S4) of placing an aluminum foil current collector having two patterned carbon plates as respective counter electrodes, placing an aluminum foil current collector between two carbon plates, applying an AC power source, and firstly etching an aluminum current collector in an electrolytic solution;

Drying the etched aluminum current collector (S5);

(S6) a step (S6) of performing secondary etching using the two carbon plates as the counter electrode after the step (S5) and placing the aluminum current collector after the first etching between the opposite electrodes;

Washing and drying the secondary etched aluminum foil (S7); And plating the current collector with nickel or tin (S8). The present invention also provides a method of manufacturing an aluminum current collector having a three-dimensional pattern structure.

The aluminum foil of step (S1) preferably has a purity of 99.00 to 99.99% and a thickness of 10 to 100 탆. If the purity is lower than 99.00, the leakage current characteristic of the EDLC is deteriorated, and aluminum purity of 100% When the thickness is less than 10 mu m, the depth that can be etched is limited to less than 10 mu m. If the depth of etching is low, the effect of the invention is lowered. If the thickness exceeds 100 mu m Since the volume of the electrode is increased at the beginning and the energy density is decreased accordingly.

If the thickness of the photosensitive liquid application is less than 0.5 占 퐉, the photosensitive liquid tends to be broken when the current collector is etched, so that the pattern is broken due to excessive etching, The drying in step (S2) is carried out at a temperature of 50 to 150 DEG C for 5 to 20 minutes at a temperature of 50 to 150 DEG C, If the drying temperature is higher than 150 ° C., the photosensitive liquid is destroyed. When the drying temperature is lower than 50 ° C., it takes a very long time to cure the photosensitive liquid at a temperature lower than 50 ° C., During the course of the process, the pattern can be easily broken down. If it exceeds 30 minutes, Gwanghan is because the pattern can not be formed correctly.

In the step S2, the mask is patterned with a chromium layer on a transparent material. The mask is placed on the aluminum current collector coated with the photosensitive liquid, and the mask is selectively irradiated with UV light. The mask is made of quartz, , And the mask has a size of 10 to 500 mu m and a pattern of 10 to 500 mu m in the interval of shape and shape. The size and the interval of the pattern shape are less than 10 mu m or less than 500 mu m The effect that the electron travels from the active material to the current collector is shortened, and the effect of the invention may be lowered.

The photosensitive liquid in step S3 is an acid or alkali solution except for neutral, and the curing in step S3 is performed at a temperature of 50 to 150 DEG C for 5 to 60 minutes. When the drying temperature is 150 DEG C If the drying time is shorter than 5 minutes, the degree of curing will be insufficient. In the subsequent etching process, the sensitizing solution is decomposed by the etchant to remove the sensitizing solution The pattern is not formed in accordance therewith, and when it exceeds 60 minutes, the photosensitive liquid is not removed smoothly in the step of removing the photosensitive liquid after excessive curing.

In the step S4, the alternating current power source has a frequency of 5 to 60 Hz and a current density of 0.1 to 10 A / cm 2. When the frequency is less than 5 Hz and the current density exceeds 10 A / cm 2, excessive etching proceeds, And the etching at the current density of more than 60 Hz and the current density exceeding 0.1 A / cm 2 proceeds less, and the etching as the pattern does not smoothly proceed. The electrolytic solution in the step (S4) Ions, 0.5 to 5 M hydrochloric acid, and 0.01 to 2 M sulfuric acid. If there is more than 20 g / l of Al ions, the disturbance of the Al ions is increased to hinder the progress of the etching, And the etching does not progress well at a sulfuric acid concentration of less than 0.01 M, and the etching proceeds excessively at a concentration of hydrochloric acid of more than 5M and a sulfuric acid concentration of more than 2M, and the primary etching at the step (S4) At 10 to 60 ° C for 10 to 60 seconds Etching is not progressed well at a temperature of less than 10 ° C and less than 10 seconds, and excessive etching occurs at a temperature of more than 60 ° C and a time of more than 60 seconds.

The drying in the step S5 is performed by washing the aluminum current collector with the distilled water and removing the residual photoresist with a sensitizer solution containing acetone for 2 to 15 minutes at a temperature of 50 to 500 DEG C, And at a temperature of less than 2 minutes, the aluminum surface is hydrated and the amorphous oxide film is formed because the aluminum film is not dried well. When the temperature exceeds 500 ° C. and the temperature exceeds 15 minutes, the aluminum surface is oxidized A crystalline oxide film may be formed, as described above.

The secondary etching in the step S6 is performed by applying an AC power to the AC power source. The AC power is preferably in the range of 10 to 90 Hz and the current density in the range of 0.1 to 10 A / cm 2. At a current density of less than 10 Hz and a current density of more than 10 A / cm 2, excessive etching may proceed and breakdown of the pattern may occur. At a current density of more than 90 Hz and a current density of less than 0.1 A / cm 2, It can not be smoothly performed.

The second etching uses an etching solution containing 10 to 30 g / l of Al ions, 100 to 300 g / l (q) Cl ions, and 5 to 30 g / l of SO 4 ions. The presence of Cl ions in an amount of more than 300 g / l and the concentration of Cl ions in an amount of 30 g / l or less can not prevent the etching process from proceeding with less than 100 g / l Cl ions and less than 5 g / l SO4 ions, it is preferable that the secondary etching is performed at 30 to 90 DEG C for 10 to 60 seconds. This is because the etching does not progress well at a temperature of less than 30 캜 and less than 10 seconds, and excessive etching may occur at a temperature of more than 90 캜 and a time of more than 60 seconds.

The washing and drying in the step S7 are performed at a temperature of 50 to 500 DEG C for 2 to 15 minutes after the washing with distilled water and the drying is not performed well at a temperature of less than 50 DEG C and less than 2 minutes The hydration reaction proceeds on the aluminum surface to form an amorphous oxide film, and the oxidation reaction proceeds on the aluminum surface at a temperature exceeding 500 ° C. and a temperature exceeding 15 minutes, so that a crystalline oxide film can be formed.

Further, the above-mentioned three-dimensional pattern in the present invention is formed by using photolithography.

The present invention also provides an aluminum current collector manufactured as described above, and provides an ultra-high capacity capacitor including such an electrode.

The coating in the step S8 is performed by plating nickel or tin having conductivity on the aluminum current collector to a predetermined thickness, so that the current collector reacts with the electrolytic solution to prevent corrosion over time, The surface can be prevented from directly reacting with the electrolytic solution, so that the corrosion resistance and the durability can be increased.

According to the present invention, there is provided a method of enlarging an aluminum current collector surface area that can effectively increase the contact area between an aluminum current collector and an active material, and a method of manufacturing an ultra-high capacity capacitor by improving the effective capacity by applying the current collector And the corrosion resistance and the durability can be increased.

1 is a photograph showing an aluminum current collector having a three-dimensional pattern structure formed by photolithography produced by way of an embodiment.
FIG. 2A is a photograph showing a pattern of a size 10 .mu.m in shape of a photoresist formed on the surface of an aluminum collector using photolithography and a pattern of 10 .mu.m apart in the intervals of the shapes. FIG.
FIG. 2B is a photograph showing a pattern of a size of 50 .mu.m formed on a surface of an aluminum collector by using photolithography and a pattern of 50 .mu.m spacing between the shapes.
FIG. 2C is a photograph showing a pattern of a size of 100 μm and an interval of shapes of 50 μm formed on a surface of an aluminum collector by photolithography using a photosensitive liquid. FIG.
FIG. 2 (d) is a photograph showing a pattern of a size of 50 .mu.m and a spacing of 10 .mu.m formed on a surface of an aluminum collector using photolithography as a photosensitive liquid.
FIG. 2 is a photograph showing a portion where a photosensitive liquid remains and a pattern of a removed portion. FIG.
FIG. 4 is a photograph showing an aluminum current collector after selectively etching only aluminum in a portion where the photosensitive liquid is removed. FIG.
FIG. 5 is a photograph showing an aluminum current collector after removing the photoresist solution remaining on the surface of the aluminum current collector with a remover after etching.
FIG. 6 is a configuration diagram of an ultra-high capacity capacitor electrode to which an aluminum current collector manufactured through an embodiment is applied. FIG.
FIG. 7 is an internal configuration diagram of an ultra-high capacity capacitor manufactured by applying an aluminum current collector manufactured through the embodiment. FIG.

In order to carry out the present invention, the purity of aluminum is 99.00 to 99.99%, the impurities are 4,000 ppm of Cu, 2,000 ppm of Si and 2,000 ppm of Fe or less. To remove 1) acetone solution 2) methanol solution 3) wash sequentially with distilled water and dry with nitrogen.

Next, a photoresist is uniformly applied on the surface of the aluminum current collector in a thickness of 0.5 to 50 μm, and then the solvent in the photoresist is evaporated to maintain the solid photosensitive liquid film state. And dried at a temperature of 150 to 150 ° C. for 5 to 30 minutes. The material is capable of transmitting ultraviolet (UV) light, such as quartz, and has a shape of 10 to 500 μm in size with chromium and an interval of 10 to 500 Mu] m is placed on the aluminum current collector coated with the photosensitive liquid, and then UV light is irradiated to selectively expose the photosensitive liquid.

Then, the developing solution (alkali solution) is sprayed on the exposed aluminum current collector to selectively remove only the exposed photosensitive solution or the unexposed photosensitive solution, and the remaining photosensitive solution is completely hardened at a temperature of 50 to 150 DEG C for 5 to 60 minutes, Thereby completing pattern formation on the entire surface.

Firstly, or later, 20 g / l or less of Al ions, 0.5 to 5 M of hydrochloric acid and 0.01 to 2 M of sulfuric acid are added to prepare a first etching electrolytic solution.

The frequency of the alternating current power source is 5 Hz to 60 Hz, the current density is 0.1 to 10 A / cm 2, and the electric current density is 0.1 to 10 A / Cm 2 and the aluminum current collector is etched for 10 to 60 seconds at the temperature of the electrolyte between 10 and 60 ° C.

The etched aluminum current collector is washed with distilled water and the remaining photosensitive solution is removed using a remover such as acetone, followed by drying at 50 to 500 ° C. for 2 to 15 minutes.

First, or afterwards, Al ions of 10 to 30 g / l, Cl ions of 100 to 300 g / l, and SO 4 ions of 5 to 30 g / l are added to prepare a second etching electrolyte.

Next, an AC power source is applied with an aluminum current collector having two carbon plates as its counter electrodes and subjected to a first-order etching, and the frequency is 10 Hz to 90 Hz, and the current density is 0.1 to 10 A / Cm < 2 > and at an electrolyte temperature of 30 to 90 [deg.] C for 10 to 60 seconds, the aluminum current collector subjected to the secondary etching is washed with distilled water and dried at 50 to 500 DEG C for 2 to 15 minutes The present invention is completed.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples. However, it should be understood that the present invention is not limited to the following examples.

[Example 1] Production of aluminum current collector having a three-dimensional pattern structure using photoresist

An aluminum foil with a purity of 99.90% and a thickness of 0.030 mm was sequentially washed with 1) acetone solution 2) methanol solution 3) distilled water, and then dried with nitrogen.

A photoresist was uniformly applied on the surface of the aluminum collector to a thickness of 0.5 탆 and dried at a temperature of 80 캜 for 15 minutes. Thereafter, a mask having a pattern of a circle having a diameter of 80 탆 and an interval of the circles of 70 탆 was formed ) Was placed on the aluminum current collector coated with the photosensitive liquid, and UV light was irradiated to selectively expose the photosensitive liquid.

The developing solution was sprayed on the exposed aluminum collector to selectively remove only the unexposed photosensitive liquid, and the remaining photosensitive liquid was completely hardened at a temperature of 100 degrees for 15 minutes to complete pattern formation on the aluminum current collector.

15 g / l of Al ions, 1 M hydrochloric acid and 2 M sulfuric acid were added to prepare a first etched electrolytic solution. Two carbon plates were used as respective counter electrodes, and an aluminum current collector patterned with a photosensitive liquid was placed therebetween, Power was applied.

The aluminum current collector was firstly etched in an electrolytic solution having an AC power source frequency of 50 Hz, a current density of 3 A / cm 2 and a temperature of 45 ° C. for 50 seconds, and the aluminum current collector thus etched was washed with distilled water. Was removed and dried at 150 DEG C for 2 minutes.

An aluminum electrolytic solution prepared by adding 10 g / l of Al ions, 120 g / l of Cl ions and 20 g / l of SO 4 ions to the second etching electrolyte, and then subjecting the two carbon plates to respective counter electrodes and subjected to the first etching, And an AC power source was applied so as to be positioned therebetween.

The frequency of the AC power source was 30 Hz, the current density was 1 A / cm 2, and the aluminum current collector was subjected to the secondary etching for 45 seconds at the electrolyte temperature of 45.

The secondary etched aluminum current collector was washed with distilled water and dried at 125 DEG C for 10 minutes.

An aluminum current collector having a three-dimensional pattern surface structure as described above is shown in Fig.

[Example 2] Fabrication of an ultra-high capacity capacitor using an aluminum current collector having a three-dimensional pattern structure

After adding 80 g of activated carbon (specific surface area: 2,100 m2 / g), 20 g of carbon black and 4 g of binder, stirring was carried out for 30 minutes using a stirrer, then 200 g of pure water was added and stirred for 200 minutes. 100 g of pure water and 4 g of binder were added, The slurry was prepared by further stirring.

The slurry was coated at 0.6 g / cm 3 on an aluminum current collector having a three-dimensional pattern structure manufactured by using a photoresist to prepare an electrode.

The electrode was subjected to primary drying at 70 ° C for 20 minutes and then secondary drying at 100 ° C for 240 minutes.

The dried electrode was cut to a size of 3.5 cm × 4.5 cm (15.75 cm 2), and two sheets were prepared. One electrode prepared in the above-described manner, the electrolytic solution, and the remaining one electrode prepared above were laminated in this order. And an aluminum pouch was put on the outside.

Electrolyte (1M TEABF4 / ACN) was put into the pouch, vacuum impregnated, and sealed to prepare a supercapacitor.

[Comparative Example]

After adding 80 g of activated carbon (specific surface area: 2,100 m2 / g), 20 g of carbon black and 4 g of binder, stirring was carried out for 30 minutes using a stirrer, then 200 g of pure water was added and stirred for 200 minutes. 100 g of pure water and 4 g of binder were added, The slurry was prepared by further stirring.

In general, the slurry was coated at 0.6 g / cm 3 on an aluminum current collector for EDLC sold in the market to prepare an electrode.

The electrode was subjected to primary drying at 70 ° C for 20 minutes and then secondary drying at 100 ° C for 240 minutes.

The dried electrode was cut to a size of 3.5 cm × 4.5 cm (15.75 cm 2), and two sheets were prepared. One electrode prepared in the above-described manner, the electrolytic solution, and the remaining one electrode prepared above were laminated in this order. Exterior is carried out with aluminum pouch.

Electrolyte (1M TEABF4 / ACN) was put into the pouch, vacuum impregnated, and sealed to prepare a supercapacitor.

[Evaluation example]

All of the ultra-high capacity capacitors prepared in Examples and Comparative Examples were charged at a constant current of 15.75 mA and a constant voltage of 2.7 V, maintained for 30 minutes, and then discharged at a constant current (15.75 mA).

The capacity was measured under the above conditions. The results are shown in Table 1.

division Example Comparative Example Capacity (F) 3.56 2.75

As can be seen from the above table, the present invention provides an aluminum current collector capable of providing an ultra-high capacity capacitor.

10: active material
20: pattern-etched aluminum collector
30: Tell me where
40: Negative electrode with patterned aluminum collector
50: Positive electrode with patterned aluminum collector

Claims (1)

Washing the aluminum foil collector and drying it with nitrogen (S1);
(S2) applying a photosensitive liquid onto the surface of the dried aluminum foil current collector and then drying to selectively expose and cure the photosensitive liquid;
After the step S2, the developer is sprayed on the exposed aluminum current collector to selectively remove the unexposed photoresist, and then the remaining photoresist is completely cured to complete the pattern formation on the aluminum current collector (S3);
(S4) of placing an aluminum foil current collector having two patterned carbon plates as respective counter electrodes, placing an aluminum foil current collector between two carbon plates, applying an AC power source, and firstly etching an aluminum current collector in an electrolytic solution;
Drying the etched aluminum current collector (S5);
A step (S6) of performing secondary etching using the two carbon plates as the counter electrode after the step (S5) and placing the aluminum current collector after the first etching between the opposite electrodes;
Washing and drying the secondary etched aluminum foil (S7); And a step (S8) of coating a conductive material on the surface of the current collector, wherein the aluminum foil in the step (S1) has a purity of 99.00 to 99.99% 100 占 퐉. A method for producing an aluminum current collector having a three-dimensional pattern structure.

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