阅读说明：本技术 一种平面式超级电容器及其制备方法 (Planar super capacitor and preparation method thereof ) 是由 谢颖熙 汤勇 白石根 林立慧 于 2020-12-25 设计创作，主要内容包括：本发明公开了一种平面式超级电容器及其制备方法,平面式超级电容器由串联的多组超级电容器构成,其以柔性高分子聚合物薄膜作为衬底和碳源,薄膜上具有成排的激光诱导石墨烯；导电集流体固定在柔性高分子聚合物薄膜上并相邻于第一个和最后一个激光诱导石墨烯,并且构成接触；凝胶电解质作为封装层,覆设在激光诱导石墨烯上且填充激光诱导石墨烯之间的间隙；平面式超级电容器通过激光刻蚀中间激光诱导石墨烯的封装层来构成电子通道和离子通道交替相接的串联结构,由凝胶电解质间隔的每两个激光诱导石墨烯构成一组超级电容器且其电解质部分作为离子通道,激光刻蚀线作为分隔不同组超级电容器的电子通道。本发明电容器具备高输出电压和紧凑型结构。(The invention discloses a planar supercapacitor and a preparation method thereof, wherein the planar supercapacitor is composed of a plurality of groups of supercapacitors which are connected in series, a flexible high polymer film is used as a substrate and a carbon source, and rows of laser-induced graphene are arranged on the film; the conductive current collector is fixed on the flexible high-molecular polymer film and is adjacent to the first laser-induced graphene and the last laser-induced graphene, and contact is formed; the gel electrolyte is used as a packaging layer, is covered on the laser-induced graphene and fills gaps among the laser-induced graphene; the planar supercapacitor is characterized in that a series structure in which electronic channels and ion channels are alternately connected is formed by laser etching of a packaging layer of middle laser-induced graphene, every two laser-induced graphene separated by gel electrolyte form a group of supercapacitors, the electrolyte part of each supercapacitor serves as an ion channel, and a laser etching line serves as an electronic channel for separating different groups of supercapacitors. The capacitor of the present invention has a high output voltage and a compact structure.)

1. A planar supercapacitor, characterized in that it is composed of a plurality of groups of supercapacitors connected in series, and the output voltage is controlled by controlling the number of supercapacitors connected in series;

the planar supercapacitor takes the same flexible high-molecular polymer film as a substrate and a carbon source, and the flexible high-molecular polymer film is provided with a plurality of rows of laser-induced graphene; the conductive current collectors are fixed on the flexible high-molecular polymer film and are adjacent to the first laser-induced graphene and the last laser-induced graphene, and the first laser-induced graphene and the last laser-induced graphene are respectively in contact with the corresponding conductive current collectors; the gel electrolyte is used as a packaging layer, is covered on the laser-induced graphene and fills gaps among different laser-induced graphene;

respectively etching the packaging layers of different laser-induced graphene positioned between the first laser-induced graphene and the last laser-induced graphene by laser; the planar supercapacitor is of a series structure in which an electronic channel and an ion channel are alternately connected through laser etching lines generated by laser etching, wherein every two laser-induced graphene separated by gel electrolyte form a group of supercapacitors, the gel electrolyte part of each supercapacitor serves as the ion channel, and the laser etching lines serve as the electronic channel and separate different groups of supercapacitors.

2. The planar supercapacitor according to claim 1, wherein the flexible polymer film is a polymer polyimide film or a polyetherimide film containing aromatic rings and imide structural units.

3. The planar supercapacitor according to claim 1, wherein the laser-induced graphene is prepared by a laser processing method, wherein the laser is emitted by a carbon dioxide infrared laser, and the wavelength of the laser is 10.6 μm.

4. The planar supercapacitor according to claim 1, wherein the conductive current collector is at least one of nickel foil, copper foil, silver paste, silver nanowires, and gold nanoparticles, and is applied on the flexible polymer film by brushing, spraying, or electrochemical deposition.

5. The planar supercapacitor according to claim 1, wherein the gel electrolyte is a mixture of a polymer backbone and a plasticizer.

6. The planar supercapacitor according to claim 5, wherein the polymer backbone is one of polyacrylate, polyethylene oxide, polyvinyl alcohol, polyacrylonitrile, polyvinylidene fluoride-co-hexafluoropropylene, polymethyl methacrylate, polyethylene glycol blended polyacrylonitrile.

7. The planar supercapacitor according to claim 5, wherein the plasticizer is a mixture of an organic solvent and a supporting electrolyte, wherein the organic solvent is two or more of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, dimethylformamide, butyrolactone, tetrahydrofuran; the supporting electrolyte is one of potassium chloride, potassium perchlorate, sulfuric acid, phosphoric acid, potassium hydroxide and potassium chloride.

8. The planar supercapacitor according to claim 1, wherein the gel electrolyte is added on the laser-induced graphene by spin coating, the thickness of the gel electrolyte layer is 0.5-1 mm, the spin coating speed is 500r/min, and the spin coating time is 5 min.

9. The planar supercapacitor according to claim 1, wherein the conductive current collector is fixed by an insulating tape, and the insulating tape is a polyimide tape.

10. A preparation method of a planar supercapacitor is characterized by comprising the following steps:

s1, using the same flexible high polymer film as a substrate and a carbon source, and then preparing a patterned electrode material by adopting a laser processing method to obtain a plurality of rows of laser-induced graphene;

s2, adding a conductive current collector on the flexible high-molecular polymer film, and enabling the conductive current collector to be adjacent to and in contact with the first laser-induced graphene and the last laser-induced graphene;

s3, adding a gel electrolyte on the laser-induced graphene for packaging, wherein the gel electrolyte covers the laser-induced graphene and fills gaps among different laser-induced graphene;

s4, for each laser-induced graphene between the first laser-induced graphene and the last laser-induced graphene, performing laser etching on the packaging layer of each laser-induced graphene to generate a laser etching line; every two laser-induced graphene separated by the gel electrolyte form a group of super capacitors, and different groups of super capacitors are separated by laser etching lines; the laser etching line is used as an electronic channel, and the gel electrolyte part of the supercapacitor is used as an ion channel, so that a series structure in which the electronic channel and the ion channel are alternately connected is formed, and the planar supercapacitor formed by a plurality of groups of supercapacitors connected in series is obtained.

Technical Field

The invention relates to the technical field of super capacitors, in particular to a planar super capacitor and a preparation method thereof.

Background

The high-voltage super capacitor is frequently applied to wearable electronic devices and integrated microcircuit systems as a power supply device due to the advantages of microminiature, portability, flexibility, long cycle life, high power/energy density and the like, and can meet the voltage output and energy supply in a certain range. However, in practical application, the application voltage of the high-density integrated electronic chip/circuit board is 3-5V, the application voltage of small electronic devices (such as smart watches, electronic clocks, temperature/humidity meters and the like) and wearable flexible electronic skin/sensors is within 3V, and the rated voltage of the mobile charging power supply is 5V. However, the stable working voltage of a common single-group super capacitor is generally about 1V, and the high-voltage design realized by the traditional conductive connection has structural redundancy, low compactness and integration performance in a high-density device integration system, and is difficult to realize high-voltage output of more than 3V in a small area range.

The existing manufacturing method is to directly process an electric connection part on a flexible substrate so as to complete the packaging of a series high-voltage structure, and although the mode is favorable for constructing a high-voltage flexible super capacitor, the whole structure of the super capacitor is difficult to further optimize, and more compact high-voltage packaging is realized. In order to increase the working voltage of the micro-miniature super capacitor, high-precision manufacturing methods such as femtosecond laser, electric ink-jet printing and the like are generally adopted to obtain a compact structure, but the equipment and manufacturing cost caused by the high-precision manufacturing methods are higher.

Disclosure of Invention

The invention aims to solve the problems of low working voltage, redundancy of a series connection electric connection part, complicated preparation process of series connection high voltage, low overall structure compactness and the like of the super capacitor, and provides the planar super capacitor which has high output voltage and a compact structure and has wide application prospect in the fields of wearable flexible devices and integrated electronics.

The second purpose of the invention is to provide a preparation method of a planar super capacitor, which can prepare a micro high-voltage super capacitor meeting the high-voltage requirements of wearable flexible devices and high-density integrated electronic facilities.

The first purpose of the invention is realized by the following technical scheme: a planar supercapacitor consisting of a plurality of groups of supercapacitors connected in series and controlling an output voltage by controlling the number of supercapacitors connected in series;

the planar supercapacitor takes the same flexible high-molecular polymer film as a substrate and a carbon source, and the flexible high-molecular polymer film is provided with a plurality of rows of laser-induced graphene; the conductive current collectors are fixed on the flexible high-molecular polymer film and are adjacent to the first laser-induced graphene and the last laser-induced graphene, and the first laser-induced graphene and the last laser-induced graphene are respectively in contact with the corresponding conductive current collectors; the gel electrolyte is used as a packaging layer, is covered on the laser-induced graphene and fills gaps among different laser-induced graphene;

respectively etching the packaging layers of different laser-induced graphene positioned between the first laser-induced graphene and the last laser-induced graphene by laser; the planar supercapacitor is of a series structure in which an electronic channel and an ion channel are alternately connected through laser etching lines generated by laser etching, wherein every two laser-induced graphene separated by gel electrolyte form a group of supercapacitors, the gel electrolyte part of each supercapacitor serves as the ion channel, and the laser etching lines serve as the electronic channel and separate different groups of supercapacitors.

Preferably, the flexible polymer film is a polymer polyimide film or a polyetherimide film containing an aromatic ring and an imide structural unit.

Preferably, the laser-induced graphene is prepared by a laser processing method, wherein laser is emitted by a carbon dioxide infrared laser, and the wavelength of the laser is 10.6 μm.

Preferably, the conductive current collector is at least one of nickel foil, copper foil, silver paste, silver nanowires and gold nanoparticles, and is added on the flexible high polymer film in a brushing, spraying or electrochemical deposition manner.

Preferably, the gel electrolyte is a mixture of a polymer backbone and a plasticizer.

Furthermore, the polymer skeleton is one of polyacrylate, polyethylene oxide, polyvinyl alcohol, polyacrylonitrile, polyvinylidene fluoride-co-hexafluoropropylene, polymethyl methacrylate and polyethylene glycol blended polyacrylonitrile.

Furthermore, the plasticizer is a mixture of an organic solvent and a supporting electrolyte, wherein the organic solvent is two or more of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, dimethyl carbonate, diethyl carbonate, dimethylformamide, butyrolactone and tetrahydrofuran; the supporting electrolyte is one of potassium chloride, potassium perchlorate, sulfuric acid, phosphoric acid, potassium hydroxide and potassium chloride.

Preferably, the gel electrolyte is added on the laser-induced graphene in a spin coating mode, the thickness of the gel electrolyte layer is 0.5-1 mm, the spin coating speed is 500r/min, and the spin coating time is 5 min.

Preferably, the conductive current collector is fixed by an insulating tape, and the insulating tape is a polyimide tape.

The second purpose of the invention is realized by the following technical scheme: a preparation method of a planar supercapacitor comprises the following steps:

s1, using the same flexible high polymer film as a substrate and a carbon source, and then preparing a patterned electrode material by adopting a laser processing method to obtain a plurality of rows of laser-induced graphene;

s2, adding a conductive current collector on the flexible high-molecular polymer film, and enabling the conductive current collector to be adjacent to and in contact with the first laser-induced graphene and the last laser-induced graphene;

s3, adding a gel electrolyte on the laser-induced graphene for packaging, wherein the gel electrolyte covers the laser-induced graphene and fills gaps among different laser-induced graphene;

s4, for each laser-induced graphene between the first laser-induced graphene and the last laser-induced graphene, performing laser etching on the packaging layer of each laser-induced graphene to generate a laser etching line; every two laser-induced graphene separated by the gel electrolyte form a group of super capacitors, and different groups of super capacitors are separated by laser etching lines; the laser etching line is used as an electronic channel, and the gel electrolyte part of the supercapacitor is used as an ion channel, so that a series structure in which the electronic channel and the ion channel are alternately connected is formed, and the planar supercapacitor formed by a plurality of groups of supercapacitors connected in series is obtained.

Compared with the prior art, the invention has the following advantages and effects:

1. the planar super capacitor based on the flexible substrate is suitable for high-density and high-voltage facilities such as wearable electronic devices, integrated microcircuits and the like, and has universality.

2. The invention can realize the series high-voltage structure with the alternately connected electronic channel and ion channel by adopting the laser processing method twice, and compared with the prior art, the preparation process of the planar super capacitor is simpler and more convenient.

3. The planar supercapacitor can output high voltage in a small area, and the actual working voltage of the supercapacitor can be effectively controlled by adjusting the quantity of the laser-induced graphene and the laser etching lines.

4. The invention can shorten the series connection electric connection part of the plane type super capacitor to the maximum extent by using processing equipment with low cost, and further compact the structure of the super capacitor.

5. The planar super capacitor has excellent electrochemical performance under continuous charge and discharge or different bending angles.

6. The conductive current collector and the gel electrolyte can be selected from various types and can be prepared according to actual conditions, so that the preparation process of the planar super capacitor is more flexible and has wider adaptability.

Drawings

FIG. 1 is a flow chart of the preparation of the planar supercapacitor according to the present invention.

FIG. 2 is an equivalent circuit diagram of the planar supercapacitor according to the present invention.

FIG. 3 is a schematic diagram showing the dimensions of the electrodes in the planar supercapacitor according to the present invention.

FIG. 4(a) is a plot of the current-voltage characteristics of nine sets of serially connected planar supercapacitors at a scan rate of 500 mV/s.

FIG. 4(b) is a capacitance performance curve of nine sets of serially connected planar supercapacitors charged and discharged 10000 times continuously at a constant current density of 10 μ A.

FIG. 5(a) is a plot of the current-voltage characteristics of nine sets of serially connected planar supercapacitors at a scan rate of 500mV/s for different bend angles.

Fig. 5(b) is a charging and discharging curve diagram of nine groups of serially connected planar supercapacitors under a constant current density of 10 mua under different bending angles.

FIG. 5(c) is a graph showing the capacitance ratio of nine sets of serially connected planar supercapacitors to the initial value at a scan rate of 500mV/s for different bending angles.

Fig. 5(d) is a diagram showing the ratio of the capacitance of nine sets of serially connected planar supercapacitors to the initial value at a constant current density of 10 μ a under different bending angles.

Detailed Description

The present invention will be described in further detail with reference to examples and drawings, but the present invention is not limited thereto.

Example 1

The embodiment discloses a planar supercapacitor, which is composed of multiple groups of supercapacitors connected in series, can output high voltage (up to 10V), and can meet the requirements of wearable flexible devices and high-density integrated electronic facilities on high voltage.

Specifically, as shown in fig. 1 and fig. 2, the planar supercapacitor uses the same flexible polymer film 1 as a substrate and a carbon source, and the flexible polymer film can be a polymer polyimide film or a polyetherimide film containing aromatic rings and imide structural units, so as to produce laser-induced graphene.

The flexible high-molecular polymer film is provided with a plurality of rows of laser-induced graphene 2, wherein the laser-induced graphene is prepared by a laser processing method, a carbon dioxide infrared laser is used as a laser source, the flexible high-molecular aromatic polymer film is irradiated by laser, most of nitrogen/oxygen elements are gasified at high temperature, and the laser-induced graphene can be formed after recombination of residual carbon elements and can be used as an electrode material of a supercapacitor. The wavelength of the laser light used in this example was 10.6 μm.

The conductive current collectors 3 are fixed on the flexible high-molecular polymer film and adjacent to the first and last laser-induced graphene, and the first and last laser-induced graphene are respectively in contact with the corresponding conductive current collectors.

The conductive current collector is used as an electric connection end, can adopt at least one of nickel foil, copper foil, silver paste, silver nanowires and gold nanoparticles, and can be added on the flexible high polymer film in a brushing, spraying or electrochemical deposition mode. In addition, in order to ensure that the conductive current collector is in close contact with the laser-induced graphene, the conductive current collector can be fixed by manually sticking an insulating tape, and the insulating tape can be a polyimide tape.

The gel electrolyte 4 is used as a packaging layer, is coated on the laser-induced graphene, and fills gaps among different laser-induced graphene. The gel electrolyte can be added on the laser-induced graphene in a spin coating mode, the thickness of the packaging layer is 0.5-1 mm, the spin coating speed is 500r/min, and the spin coating time is 5 min.

The gel electrolyte is a mixture of a polymer skeleton and a plasticizer, and the polymer skeleton can be one of polyacrylate, polyethylene oxide, polyvinyl alcohol, polyacrylonitrile, polyvinylidene fluoride-co-hexafluoropropylene, polymethyl methacrylate and polyethylene glycol blended polyacrylonitrile.

The plasticizer is a mixture of an organic solvent and a supporting electrolyte, wherein the organic solvent can be two or more of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, dimethyl carbonate, diethyl carbonate, dimethylformamide, butyrolactone and tetrahydrofuran; the supporting electrolyte may be one of potassium chloride, potassium perchlorate, sulfuric acid, phosphoric acid, potassium hydroxide, potassium chloride.

The different laser-induced graphene layers between the first and last laser-induced graphene layers are laser-etched to convert the gel electrolyte into a conductive carbon material, thereby forming a laser-etched line 5. Every two laser induced graphene separated by a gel electrolyte constitute a group of supercapacitors, and different groups of supercapacitors are separated by a laser etched line. The laser used for etching in this embodiment is a carbon dioxide laser.

The gel electrolyte part of the supercapacitor can be used as an ion channel, the laser etching line can be used as an electron channel, the planar supercapacitor can form a series structure in which the electron channel and the ion channel are alternately connected, namely the planar supercapacitor is formed by a plurality of groups of supercapacitors which are connected in series, the series number of the supercapacitors can be controlled by controlling the number of the laser-induced graphene and the laser etching line, and further the output voltage can be controlled.

As shown in fig. 3, the size (width × length) of the planar supercapacitor according to the present embodiment may be 3mm × 21.15mm, wherein the graphene electrode shape may be set to be rectangular, the electrode size (width × length) may be two types, 3mm × 1mm and 3mm × 2mm, and the distance between the electrodes may be set to be 0.35 mm. In addition, the size (width × length) of the planar supercapacitor may be 0.5mm × 5.5mm, two kinds of the electrode sizes (width × length) of 0.5mm × 0.3mm and 0.5mm × 0.8mm may be used, and the pitch between the electrodes may be set to 0.34 mm.

Example 2

This embodiment discloses a method for preparing a planar supercapacitor, which can be used to prepare the planar supercapacitor in embodiment 1, as shown in fig. 1 and 2, and includes the following steps:

s1, the same flexible high polymer film is used as a substrate and a carbon source, and then a laser processing method is adopted to prepare the patterned electrode material, so that a plurality of rows of laser-induced graphene are obtained.

And S2, adding a conductive current collector on the flexible high-molecular polymer film, and enabling the conductive current collector to be adjacent to and in contact with the first laser-induced graphene and the last laser-induced graphene.

And S3, adding a gel electrolyte on the laser-induced graphene for packaging, wherein the gel electrolyte covers the laser-induced graphene and fills gaps among different laser-induced graphene.

At this time, as shown in fig. 2, the laser-induced graphene located between the first and last laser-induced graphene does not yet form a series structure, the entire row of laser-induced graphene corresponds to one capacitor C, the two conductive current collectors correspond to resistors Rg and Re, and the entire device corresponds to a circuit formed by the resistor Rg, the capacitor C, and the resistor Re connected in sequence.

S4, for each laser-induced graphene between the first laser-induced graphene and the last laser-induced graphene, performing laser etching on the packaging layer of each laser-induced graphene to generate a laser etching line; every two laser-induced graphenes separated by a gel electrolyte constitute a group of supercapacitors, with different groups of supercapacitors separated by laser etched lines. The laser etching line is used as an electronic channel, and the gel electrolyte part of the supercapacitor is used as an ion channel, so that a series structure in which the electronic channel and the ion channel are alternately connected is formed, and the planar supercapacitor formed by a plurality of groups of supercapacitors connected in series is obtained.

At this time, as shown in fig. 2, each supercapacitor is equivalent to a capacitor, each conductive current collector and each laser etching line are equivalent to a resistor, and the whole element is equivalent to a circuit in which the resistor and the capacitor are alternately connected.

To better describe the preparation method of this example, two specific examples are shown below.

Example one:

(1-1) sticking a polyimide film with the thickness of 120 mu m and the width of 50mm on a glass sheet, cleaning the surface of the film by using alcohol and deionized water, then placing the film on a heating platform, and drying the surface of the film at 50 ℃;

(1-2) setting the laser power of carbon dioxide to be 2W, setting the scanning speed to be 30mm/s and the laser focal length to be 23mm, and processing rectangular pair patterned graphene electrodes with the dimension length of 3mm multiplied by 21.15mm at one time;

(1-3) adding 2g of polyvinyl alcohol powder (with the molecular weight of 85000-98000) into 20mL of deionized water, magnetically stirring (with the stirring speed of 500r/min) in a water bath at 85 ℃ until the solution becomes clear, then naturally cooling the gel solution for 30min at room temperature, then injecting 10mL of potassium chloride solution (with the concentration of 4mol/L) into the gel solution, and magnetically stirring (with the stirring speed of 500r/min) for 30min at room temperature to obtain a gel electrolyte;

(1-4) coating conductive silver paste on the electric connection parts at two ends of a graphene electrode, pasting a copper foil with the width of 5mm, and fixing the copper foil by using a polyimide adhesive tape to ensure that a conductive current collector is in close contact with an electrode material;

(1-5) dripping 10mL of gel electrolyte in the middle of the electrode material, placing a glass sheet on a spin coater, spin-coating for 10s at the rotating speed of 300r/min, placing for 12h, and removing the redundant electrolyte layer by using a knife after the electrolyte is solidified;

(1-6) setting the laser power of the carbon dioxide at 2W, the scanning speed at 20mm/s and the laser focal length at 23mm, processing eight laser etching lines at one time to realize the series connection of nine groups of supercapacitors, and preparing the planar miniature high-voltage supercapacitor with the output voltage of 10V.

Example two:

(2-1) sticking a polyimide film with the thickness of 120 mu m and the width of 30mm on a glass sheet, cleaning the surface of the film by using alcohol and deionized water, then placing the film on a heating platform, and drying the surface of the film at 50 ℃;

(2-2) setting the laser power of the carbon dioxide to be 2W, setting the scanning speed to be 30mm/s, setting the laser focal length to be 23mm, and processing rectangular pair patterned graphene electrodes with the dimension length of 0.5mm multiplied by 5.5mm at one time;

(2-3) adding 2g of polyvinyl alcohol powder (with the molecular weight of 85000-98000) into 20mL of deionized water, magnetically stirring (500r/min) in a water bath at 85 ℃ until the solution is clear, naturally cooling the gel solution at room temperature for 30min, then injecting 10mL of potassium chloride solution (with the concentration of 4mol/L) into the gel solution, and magnetically stirring (with the stirring speed of 500r/min) at room temperature for 30min to obtain a gel electrolyte;

(2-4) coating conductive silver paste on the electric connection parts at two ends of the graphene electrode, pasting a copper foil with the width of 5mm, and fixing the copper foil by using a polyimide adhesive tape to ensure that a conductive current collector is in close contact with an electrode material;

(2-5) dripping 10mL of gel electrolyte in the middle of the electrode material, placing a glass sheet on a spin coater, spin-coating for 10s at the rotating speed of 300r/min, placing for 12h, and removing the redundant electrolyte layer by using a knife after the electrolyte is solidified;

(2-6) setting the laser power of the carbon dioxide at 2W, the scanning speed at 20mm/s and the laser focal length at 23mm, processing four laser etching lines at one time to realize series connection of five groups of super capacitors, and preparing the planar micro high-voltage super capacitor with the output voltage of 5V.

In addition, the present embodiment also provides the electrochemical performance test results of the planar supercapacitor of the first embodiment, which can be seen in fig. 4(a), fig. 4(b), and fig. 5(a) to fig. 5 (d). As can be seen from fig. 4(a) to 5(d), the planar supercapacitor prepared by the method of the present embodiment can achieve a high voltage output of 10V in a small area. The super capacitor has stable electrochemical performance, can be continuously charged and discharged 10000 times under the constant current density of 10 muA, and the capacitance is kept to 91.6 percent of the initial value; the voltammetry and constant current charge and discharge performance were tested at different bending angles, the capacitance was maintained at 98.54% of the initial value at a scan rate of 500mV/s and 97.83% of the initial value at a current density of 10 μ A.

Therefore, the planar type super capacitor formed by a plurality of super capacitors connected in series has the advantages of microminiature, portability, flexibility, high cycle life and high power/energy density, and therefore can meet the requirements of wearable flexible devices and high-density integrated electronic facilities.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.