A method for preparing a novel electrode material based on a flexible substrate

Abstract

This invention relates to the field of electrode material technology, and in particular to a method for preparing a novel electrode material based on a flexible substrate. The method uses a PET film as a substrate, performs surface modification using ultraviolet ozone method, grows a covalent organic framework in situ on its surface and grafts a sulfonate anion structure, and achieves strong adhesion of silver nanowires on the PET film through electrostatic interaction and structural interlocking, as well as photo-chemical welding. At the same time, it also has high light transmittance and good electrical conductivity.

Description

Technical Field

[0001] This invention relates to the field of electrode material technology, and in particular to a method for preparing a novel electrode material based on a flexible substrate. Background Technology

[0002] Transparent electrodes are core components of modern optoelectronic devices such as flexible displays, touchscreens, and organic solar cells. Indium tin oxide (ITO) thin films are widely used in the market; however, ITO films are brittle and prone to cracking under repeated bending, leading to a sharp increase in resistance and even failure. This makes them unsuitable for the stringent flexibility requirements of emerging fields such as wearable devices. Silver nanowire networks are considered one of the most promising candidates to replace ITO films due to their high conductivity, high light transmittance, and intrinsic flexibility; however, they also have some limitations.

[0003] First, the silver nanowires only form contact points through physical overlap. These junctions exhibit significant contact resistance, becoming a bottleneck restricting overall conductivity. Current methods typically employ thermal annealing to soften or decompose the polymer coating at the silver nanowire junctions, promoting metal fusion and reducing contact resistance. However, the required temperature is far higher than the glass transition temperature of flexible substrates such as PET, easily leading to substrate shrinkage, deformation, or even melting, damaging the device structure. Second, the physical adhesion between silver nanowires and polymer substrates is weak, making them prone to slippage and detachment under friction or bending stress, resulting in unstable circuit performance or even failure. While rotating conductive polymers or using adhesives can enhance adhesion, conductive polymers generally have low conductivity, sacrificing overall conductivity, and adhesives can block some conductive pathways, similarly leading to performance degradation. Therefore, developing a flexible transparent electrode that simultaneously achieves low contact resistance, high stability, and strong adhesion has become a pressing technical problem in this field. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a novel electrode material preparation method based on a flexible substrate. This method uses a PET film as a substrate, performs surface modification using ultraviolet ozone, grows a covalent organic framework in situ on its surface and grafts a sulfonate anion structure, and achieves strong adhesion of silver nanowires on the PET film through electrostatic interaction, structural interlocking, and photo-chemical welding. At the same time, it also has high light transmittance and good electrical conductivity.

[0005] To achieve the above objectives, the present invention employs the following technical solution: a method for preparing a novel electrode material based on a flexible substrate, comprising the following steps: Step S1: Weigh the following raw materials by weight: 0.34-0.38 parts silver nitrate, 0.004-0.005 parts mercapto ionic liquid, 0.01-0.011 parts acetic acid, 20-22 parts deionized water, and 40-42 parts silver nanowire ethanol solution. Mix the silver nitrate, mercapto ionic liquid, acetic acid, and deionized water, and stir at room temperature for 15-20 minutes. Then add the silver nanowire solution and continue stirring for 30-40 minutes to obtain the electrode coating solution. The mass fraction of the silver nanowire ethanol solution is 0.25%. Step S2: Using a spin coater, spin coat the flexible substrate with electrode coating solution (0.8-1 mL). The temperature is room temperature. First, spin coat at 500 rpm for 20 seconds, then at 3000 rpm for 30 seconds. Repeat the spin coating 3-4 times. Then dry at 60℃ for 10-15 minutes. Finally, place under a xenon lamp at a light power density of 8 J / cm². 2 A novel electrode material based on a flexible substrate was prepared by photowelding under an irradiation time of 5 seconds.

[0006] The flexible substrate is prepared by the following steps: Step A1: 2,4,6-tris(4-bromophenyl)-1,3,5-triazine and tetrahydrofuran were mixed and stirred at a stirring rate of 100-120 rpm and a temperature of -78°C. Then n-butyllithium was added and stirred for 3-4 h. N,N-dimethylformamide was then added, the temperature was raised to 25°C, and the mixture was stirred for 10-12 h. Hydrochloric acid solution was then added and stirred for 1-2 h. The mixture was then distilled under reduced pressure, extracted with chloroform, and the organic layer was washed with saturated sodium chloride solution. The mixture was then distilled under reduced pressure and dried to obtain the aldehyde intermediate. Furthermore, in step A1, the volume ratio of 2,4,6-tris(4-bromophenyl)-1,3,5-triazine, tetrahydrofuran, n-butyllithium, N,N-dimethylformamide, and hydrochloric acid solution is 6.4-6.5g: 180-200mL: 5.6-5.8mL: 10-15mL: 70-80mL, and the mass fraction of the hydrochloric acid solution is 10%.

[0007] Step A2: Cut the PET film into 10cm×10cm pieces and place them in a UV ozone cleaner. Under conditions of 50% relative humidity, 30℃ temperature, 254nm UV lamp, and 250W power, perform UV ozone treatment for 8-10 minutes. Wash with deionized water and dry to obtain a pretreated PET film. Mix 4,4'-diaminobiphenyl, aldehyde intermediate, trimethylbenzene, and ethanol and ultrasonically disperse for 15-20 minutes to obtain a mixture system. Place the pretreated PET film in a container and pour in the mixture system. Let it stand for 15-20 minutes, then add acetic acid solution. React at 25℃ for 24 hours. Filter, wash, and dry to obtain a modified PET film. Furthermore, in step A2, the ratio of 4,4'-diaminobiphenyl, aldehyde intermediate, trimethylbenzene, ethanol, and acetic acid solution is 0.62-0.64g: 1.4-1.5g: 40-50mL: 40-50mL: 10-12mL, and the mass fraction of acetic acid solution is 40%.

[0008] Step A3: Sodium 4-vinylbenzenesulfonate, 2,3-dichloro-5,6-dicyanobenzoquinone, boron trifluoride diethyl ether and N,N-dimethylformamide are mixed and ultrasonically dispersed for 10-15 min. Then, the mixture is added to a container containing a modified PET film and reacted at 80°C for 48 h. After filtration, the mixture is washed with deionized water / ethanol and dried to obtain a flexible substrate. Furthermore, in step A3, the ratio of sodium 4-vinylbenzenesulfonate, 2,3-dichloro-5,6-dicyanobenzoquinone, boron trifluoride ether, and N,N-dimethylformamide is 0.8-0.9g: 0.28-0.3g: 0.4-0.42g: 30-35mL.

[0009] Furthermore, in the preparation process of the flexible substrate, n-butyllithium is first reacted with 2,4,6-tris(4-bromophenyl)-1,3,5-triazine via a lithium-halogen exchange reaction to form an intermediate structure containing aryl lithium. This intermediate then undergoes a nucleophilic addition reaction with N,N-dimethylformamide to form an aldehyde structure, thus obtaining an aldehyde intermediate. Using PET film as the substrate for the flexible substrate, it is first pretreated with ultraviolet ozone, which causes some ester bonds in the PET film to break, forming oxygen-containing functional groups, thereby changing the surface polarity of the PET film and forming active sites. Then, 4,4'-diaminobiphenyl and the aldehyde intermediate are used as monomers, where the amino group reacts with the aldehyde group to form an imine bond. Due to the pretreatment of the PET film, a uniformly dispersed covalent organic framework structure is formed on the surface of the pretreated PET film, resulting in a modified PET film. Finally, it is processed using Povarov... The reaction, using 2,3-dichloro-5,6-dicyanobenzoquinone and boron trifluoride diethyl ether as catalysts, involves grafting sodium 4-vinylbenzenesulfonate onto the aromatic ring framework formed on a modified PET film, converting the imine bonds to quinoline and introducing a benzenesulfonic acid anion structure to prepare a flexible substrate. The reaction is described in the attached instruction manual. Figure 2 , Figure 3 .

[0010] The thiol ionic liquid is prepared by the following steps: 1-Methyl-2-mercaptoimidazole and ethanol were mixed and stirred at 150-180 rpm and 75 °C. 1,3-Propanesulfonyl lactone was added, and the mixture was reacted for 6-8 h. The mixture was filtered, washed with ethyl acetate / ether, and dried to obtain the precursor. The precursor was mixed with deionized water, stirred, and hydrochloric acid solution was added. The mixture was stirred at 150-180 rpm and 90 °C, and the mixture was reacted for 12 h. The mixture was then distilled under reduced pressure, washed with ether, and dried to obtain the mercapto ionic liquid. Furthermore, in the preparation process of the thiol ionic liquid: the ratio of 1-methyl-2-mercaptoimidazole, ethanol, 1,3-propanesulfonyl lactone, deionized water and hydrochloric acid solution is 11.4-11.5g: 80-90mL: 12.2-12.3g: 30-35mL: 18-20mL, and the mass fraction of hydrochloric acid solution is 38%.

[0011] Furthermore, in the preparation process of the thiol ionic liquid, an imidazolium structure is formed by the ring-opening reaction of 1,3-propanesulfonyl lactone with 1-methyl-2-mercaptoimidazole, and a sulfonic acid group is introduced. Then, acid exchange with hydrochloric acid solution is performed to obtain the thiol ionic liquid. The reaction is described in the appendix to the specification. Figure 4 .

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention discloses a method for preparing a novel electrode material based on a flexible substrate. It uses a PET film as a substrate, performs surface modification by ultraviolet ozone method, grows a covalent organic framework in situ on its surface and grafts a sulfonate anion structure, and achieves strong adhesion of silver nanowires on the PET film through electrostatic interaction and structural interlocking, as well as photo-chemical composite welding. At the same time, it also has high light transmittance and good electrical conductivity.

[0013] This invention employs a method of introducing a mercapto-ionic liquid into the electrode coating solution and pre-mixing it with silver nitrate. The mercapto-ionic liquid's reducing properties chemically reduce silver ions, forming silver nanoparticles. The in-situ generated silver atoms deposit at the junctions of silver nanowires, achieving gentle chemical welding. Subsequent photowelding using pulsed light further enhances the process, forming a photo-chemical composite weld. This results in a synergistic effect, achieving junction welding performance comparable to high-temperature annealing under process conditions far below the PET film damage threshold. Ultimately, a low-resistance conductive network is obtained while maintaining the performance of the PET film. Furthermore, a benzenesulfonic acid-grafted covalent organic framework is constructed in situ on the PET film as an interface layer. The porous structure provides anchoring points for the silver nanowires and creates a mechanical interlocking effect. Simultaneously, the abundant sulfonate anions on its surface can tightly bind to the silver nanowires and positively charged ionic liquid components through strong electrostatic interactions, fundamentally solving the problem of poor adhesion between the silver nanowires and the substrate, and exhibiting excellent mechanical stability under bending conditions. Furthermore, due to the benzenesulfonic acid structure and the introduced mercapto ionic liquid in the covalent organic framework, their combination with the conductive network of the silver nanowires results in minimal changes in electrical properties after multiple bends, while maintaining stable performance. Through process control, excellent conductivity is achieved while maintaining high visible light transmittance, thus optimizing the overall optoelectronic performance. Attached Figure Description

[0014] Figure 1 This is a process flow diagram of the present invention; Figure 2 This is a schematic diagram of the reaction process for preparing the modified PET film of this invention; Figure 3 This is a schematic diagram of the reaction process for preparing the flexible substrate of the present invention; Figure 4 This is a schematic diagram of the reaction for preparing the thiol ionic liquid of the present invention. Detailed Implementation

[0015] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with existing known technologies. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0016] The PET films used in the following examples and comparative examples are from South China Xiangcheng Technology Co., Ltd., and the film thickness is 125µm.

[0017] Example 1: A method for preparing a novel electrode material based on a flexible substrate, comprising the following steps: Step S1: Weigh the following raw materials by weight: 0.34 parts silver nitrate, 0.004 parts mercapto ionic liquid, 0.01 parts acetic acid, 20 parts deionized water and 40 parts silver nanowire ethanol solution. Mix the silver nitrate, mercapto ionic liquid, acetic acid and deionized water, stir at room temperature for 15 min, then add the silver nanowire solution and continue stirring for 30 min to obtain the electrode coating solution. The mass fraction of the silver nanowire ethanol solution is 0.25%. Step S2: Using a spin coater, spin coat the flexible substrate with electrode coating solution (1 mL). The temperature is room temperature. First, spin coat at 500 rpm for 20 seconds, then at 3000 rpm for 30 seconds, repeating the spin coat three times. After drying at 60℃ for 10 minutes, place the substrate under a xenon lamp at a light power density of 8 J / cm². 2 A novel electrode material based on a flexible substrate was prepared by photowelding under an irradiation time of 5 seconds.

[0018] The flexible substrate is prepared by the following steps: Step A1: 2,4,6-tris(4-bromophenyl)-1,3,5-triazine and tetrahydrofuran were mixed and stirred at 100 rpm and -78°C. Then n-butyllithium was added and stirred for 3 h. N,N-dimethylformamide was added, the temperature was raised to 25°C and stirred for 10 h. Then hydrochloric acid solution was added and stirred for 1-2 h. The mixture was then distilled under reduced pressure, extracted with chloroform, washed with saturated sodium chloride solution, distilled under reduced pressure, and dried to obtain the aldehyde intermediate. Furthermore, in step A1, the ratio of 2,4,6-tris(4-bromophenyl)-1,3,5-triazine, tetrahydrofuran, n-butyllithium, N,N-dimethylformamide, and hydrochloric acid solution is 6.4g:180mL:5.6mL:10mL:70mL, and the mass fraction of hydrochloric acid solution is 10%.

[0019] Step A2: Cut the PET film into 10cm×10cm pieces and place them in a UV ozone cleaner. Under conditions of 50% relative humidity, 30℃ temperature, 254nm UV lamp, and 250W power, perform UV ozone treatment for 8 minutes. After cleaning with deionized water and drying, a pretreated PET film is obtained. Mix 4,4'-diaminobiphenyl, aldehyde intermediate, trimethylbenzene, and ethanol, and ultrasonically disperse for 15 minutes to obtain a mixture system. Place the pretreated PET film in a container and pour in the mixture system. Let it stand for 15 minutes, then add acetic acid solution. React at 25℃ for 24 hours. Filter, wash, and dry to obtain a modified PET film. Furthermore, in step A2, the ratio of 4,4'-diaminobiphenyl, aldehyde intermediate, trimethylbenzene, ethanol, and acetic acid solution is 0.62g:1.4g:40mL:40mL:10mL, and the mass fraction of acetic acid solution is 40%.

[0020] Step A3: Sodium 4-vinylbenzenesulfonate, 2,3-dichloro-5,6-dicyanobenzoquinone, boron trifluoride diethyl ether and N,N-dimethylformamide are mixed and ultrasonically dispersed for 10 min. Then, the mixture is added to a container containing a modified PET film and reacted at 80°C for 48 h. After filtration, the mixture is washed with deionized water / ethanol and dried to obtain a flexible substrate. Furthermore, in step A3, the ratio of sodium 4-vinylbenzenesulfonate, 2,3-dichloro-5,6-dicyanobenzoquinone, boron trifluoride ether, and N,N-dimethylformamide is 0.8g:0.28g:0.4g:30mL.

[0021] The thiol ionic liquid is prepared by the following steps: 1-Methyl-2-mercaptoimidazole and ethanol were mixed and stirred at 180 rpm and 75 °C. 1,3-Propanesulfonyl lactone was added and the mixture was reacted for 6 h. The mixture was filtered, washed with ethyl acetate / ether, and dried to obtain the precursor. The precursor was mixed with deionized water, stirred, and hydrochloric acid solution was added. The mixture was stirred at 150 rpm and 90 °C and reacted for 12 h. The mixture was then distilled under reduced pressure, washed with ether, and dried to obtain the mercapto ionic liquid. Furthermore, in the preparation process of the mercapto ionic liquid: the ratio of 1-methyl-2-mercaptoimidazole, ethanol, 1,3-propanesulfonyl lactone, deionized water and hydrochloric acid solution is 11.5g:80mL:12.3g:35mL:18mL, and the mass fraction of hydrochloric acid solution is 38%.

[0022] Example 2: A method for preparing a novel electrode material based on a flexible substrate, comprising the following steps: Step S1: Weigh the following raw materials by weight: 0.38 parts silver nitrate, 0.004 parts mercapto ionic liquid, 0.01 parts acetic acid, 22 parts deionized water and 40 parts silver nanowire ethanol solution. Mix the silver nitrate, mercapto ionic liquid, acetic acid and deionized water, stir at room temperature for 20 min, then add the silver nanowire solution and continue stirring for 30 min to obtain the electrode coating solution. The mass fraction of the silver nanowire ethanol solution is 0.25%. Step S2: Using a spin coater, 0.8 mL of electrode coating solution was used to spin coat the flexible substrate at room temperature. The spin coating was first performed at 500 rpm for 20 seconds, then at 3000 rpm for 30 seconds, repeated three times. The substrate was then dried at 60°C for 15 minutes and then placed under a xenon lamp at a light power density of 8 J / cm². 2 A novel electrode material based on a flexible substrate was prepared by photowelding under an irradiation time of 5 seconds.

[0023] The flexible substrate is prepared by the following steps: Step A1: 2,4,6-tris(4-bromophenyl)-1,3,5-triazine and tetrahydrofuran were mixed and stirred at 120 rpm and -78°C. Then n-butyllithium was added and stirred for 4 h. N,N-dimethylformamide was added, the temperature was raised to 25°C and stirred for 10 h. Then hydrochloric acid solution was added and stirred for 2 h. The mixture was then distilled under reduced pressure, extracted with chloroform, washed with saturated sodium chloride solution, distilled under reduced pressure, and dried to obtain the aldehyde intermediate. Furthermore, in step A1, the ratio of 2,4,6-tris(4-bromophenyl)-1,3,5-triazine, tetrahydrofuran, n-butyllithium, N,N-dimethylformamide, and hydrochloric acid solution is 6.4g:180mL:5.6mL:10mL:80mL, and the mass fraction of hydrochloric acid solution is 10%.

[0024] Step A2: Cut the PET film into 10cm×10cm pieces and place them in a UV ozone cleaner. Under conditions of 50% relative humidity, 30℃ temperature, 254nm UV lamp, and 250W power, perform UV ozone treatment for 8 minutes. After cleaning with deionized water and drying, a pretreated PET film is obtained. Mix 4,4'-diaminobiphenyl, aldehyde intermediate, trimethylbenzene, and ethanol, and ultrasonically disperse for 20 minutes to obtain a mixture system. Place the pretreated PET film in a container and pour in the mixture system. Let it stand for 15 minutes, then add acetic acid solution. React at 25℃ for 24 hours. Filter, wash, and dry to obtain a modified PET film. Furthermore, in step A2, the ratio of 4,4'-diaminobiphenyl, aldehyde intermediate, trimethylbenzene, ethanol, and acetic acid solution is 0.64g:1.5g:40mL:40mL:12mL, and the mass fraction of acetic acid solution is 40%.

[0025] Step A3: Sodium 4-vinylbenzenesulfonate, 2,3-dichloro-5,6-dicyanobenzoquinone, boron trifluoride diethyl ether and N,N-dimethylformamide are mixed and ultrasonically dispersed for 10 min. Then, the mixture is added to a container containing a modified PET film and reacted at 80°C for 48 h. After filtration, the mixture is washed with deionized water / ethanol and dried to obtain a flexible substrate. Furthermore, in step A3, the ratio of sodium 4-vinylbenzenesulfonate, 2,3-dichloro-5,6-dicyanobenzoquinone, boron trifluoride ether, and N,N-dimethylformamide is 0.9g:0.3g:0.4g:30mL.

[0026] The thiol ionic liquid is prepared by the following steps: 1-Methyl-2-mercaptoimidazole and ethanol were mixed and stirred at 150 rpm and 75 °C. 1,3-Propanesulfonyl lactone was added and the mixture was reacted for 6 h. The mixture was filtered, washed with ethyl acetate / ether, and dried to obtain the precursor. The precursor was mixed with deionized water, stirred, and hydrochloric acid solution was added. The mixture was reacted at 150 rpm and 90 °C for 12 h. The mixture was then distilled under reduced pressure, washed with ether, and dried to obtain the mercapto ionic liquid. Furthermore, in the preparation process of the thiol ionic liquid: the ratio of 1-methyl-2-mercaptoimidazole, ethanol, 1,3-propanesulfonyl lactone, deionized water and hydrochloric acid solution is 11.4g:80mL:12.2g:30mL:18mL, and the mass fraction of hydrochloric acid solution is 38%.

[0027] Example 3: A method for preparing a novel electrode material based on a flexible substrate, comprising the following steps: Step S1: Weigh the following raw materials by weight: 0.38 parts silver nitrate, 0.005 parts mercapto ionic liquid, 0.011 parts acetic acid, 22 parts deionized water and 42 parts silver nanowire ethanol solution. Mix the silver nitrate, mercapto ionic liquid, acetic acid and deionized water, stir at room temperature for 20 min, then add the silver nanowire solution and continue stirring for 40 min to obtain the electrode coating solution. The mass fraction of the silver nanowire ethanol solution is 0.25%. Step S2: Using a spin coater, spin coat the flexible substrate with electrode coating solution (1 mL). The temperature is room temperature. First, spin coat at 500 rpm for 20 seconds, then at 3000 rpm for 30 seconds, repeating the spin coat four times. Afterward, dry at 60℃ for 15 minutes, then place under a xenon lamp at a light power density of 8 J / cm². 2 A novel electrode material based on a flexible substrate was prepared by photowelding under an irradiation time of 5 seconds.

[0028] The flexible substrate is prepared by the following steps: Step A1: 2,4,6-tris(4-bromophenyl)-1,3,5-triazine and tetrahydrofuran were mixed and stirred at 120 rpm and -78°C. Then n-butyllithium was added and stirred for 4 h. N,N-dimethylformamide was added, the temperature was raised to 25°C and stirred for 12 h. Then hydrochloric acid solution was added and stirred for 2 h. The mixture was then distilled under reduced pressure, extracted with chloroform, washed with saturated sodium chloride solution, distilled under reduced pressure and dried to obtain the aldehyde intermediate. Furthermore, in step A1, the ratio of 2,4,6-tris(4-bromophenyl)-1,3,5-triazine, tetrahydrofuran, n-butyllithium, N,N-dimethylformamide, and hydrochloric acid solution is 6.5g:200mL:5.8mL:15mL:80mL, and the mass fraction of hydrochloric acid solution is 10%.

[0029] Step A2: Cut the PET film into 10cm×10cm pieces and place them in a UV ozone cleaner. Under conditions of 50% relative humidity, 30℃ temperature, 254nm UV lamp, and 250W power, perform UV ozone treatment for 10 minutes. Wash with deionized water and dry to obtain a pretreated PET film. Mix 4,4'-diaminobiphenyl, aldehyde intermediate, trimethylbenzene, and ethanol and ultrasonically disperse for 20 minutes to obtain a mixture system. Place the pretreated PET film in a container and pour in the mixture system. Let it stand for 20 minutes, then add acetic acid solution. React at 25℃ for 24 hours. Filter, wash, and dry to obtain a modified PET film. Furthermore, in step A2, the ratio of 4,4'-diaminobiphenyl, aldehyde intermediate, trimethylbenzene, ethanol, and acetic acid solution is 0.64g:1.5g:50mL:50mL:12mL, and the mass fraction of acetic acid solution is 40%.

[0030] Step A3: Sodium 4-vinylbenzenesulfonate, 2,3-dichloro-5,6-dicyanobenzoquinone, boron trifluoride diethyl ether and N,N-dimethylformamide are mixed and ultrasonically dispersed for 15 min. Then, the mixture is added to a container containing a modified PET film and reacted at 80°C for 48 h. After filtration, the mixture is washed with deionized water / ethanol and dried to obtain a flexible substrate. Furthermore, in step A3, the ratio of sodium 4-vinylbenzenesulfonate, 2,3-dichloro-5,6-dicyanobenzoquinone, boron trifluoride ether, and N,N-dimethylformamide is 0.9g:0.3g:0.42g:35mL.

[0031] The thiol ionic liquid is prepared by the following steps: 1-Methyl-2-mercaptoimidazole and ethanol were mixed and stirred at 180 rpm and 75 °C. 1,3-Propanesulfonyl lactone was added and the mixture was reacted for 8 h. The mixture was filtered, washed with ethyl acetate / ether, and dried to obtain a precursor. The precursor was mixed with deionized water, stirred, and hydrochloric acid solution was added. The mixture was stirred at 180 rpm and 90 °C and reacted for 12 h. The mixture was then distilled under reduced pressure, washed with ether, and dried to obtain a mercapto ionic liquid. Furthermore, in the preparation process of the thiol ionic liquid: the ratio of 1-methyl-2-mercaptoimidazole, ethanol, 1,3-propanesulfonyl lactone, deionized water and hydrochloric acid solution is 11.5g:90mL:12.3g:35mL:20mL, and the mass fraction of hydrochloric acid solution is 38%.

[0032] Comparative Example 1: Compared with Example 3, this comparative example replaces 1-methyl-2-mercaptoimidazole in the preparation process of mercapto ionic liquid in Example 3 with 1-methylimidazole, while the other steps are the same.

[0033] Comparative Example 2: Compared with Example 3, the pretreatment PET film in the flexible substrate preparation process of Example 3 was replaced with a PET film, while the other steps were the same.

[0034] Comparative Example 3: Compared with Example 3, the flexible substrate in the preparation process of the novel electrode material based on the flexible substrate in Example 3 was replaced with the modified PET film of Example 3, while the other steps were the same.

[0035] Comparative Example 4: Compared with Example 3, the photowelding step in the preparation process of the novel electrode material based on a flexible substrate in Example 3 is removed, while the other steps are the same.

[0036] The novel electrode materials based on flexible substrates prepared in Examples 1, 2, 3, Comparative Examples 1, 2, 3, and 4 were fabricated into 5cm × 5cm samples. The transmittance of the conductive thin film substrate material was measured using a UV-Vis spectrophotometer at a wavelength of 550nm, with a PET film as the baseline. The sheet resistance of the conductive thin film substrate material was tested using a micro-ohmmeter via a four-probe method. The conductive thin film substrate material was then bent in the same manner at a bending angle of 180° for 2000 bends. The sheet resistance after bending was recorded, and the rate of change of sheet resistance was calculated as: (Sheet resistance after bending - Initial sheet resistance) / Initial sheet resistance * 100%. The test results are shown in the table below. Table 1 Test Results As shown in the table, the test results show that when comparing Examples 1, 2, and 3 with Comparative Examples 1, 2, 3, and 4, Examples 1, 2, and 3 achieve a synergistic effect of photo-chemical composite welding. The chemical welding provides the initial silver bridge, while the photo-welding achieves deep fusion, resulting in extremely low resistance at the junction of the silver nanowires and their combination with the introduced covalent organic framework. This results in a sheet resistance of around 25 Ω / sq, demonstrating good conductivity. At the same time, the ultraviolet ozone pretreatment firmly anchors the covalent organic framework onto the PET film, and the introduction of benzenesulfonic acid groups through modification and the locking of the silver nanowires through strong electrostatic action maintain good light transmittance while ensuring multiple bending performance. In Comparative Example 1, 1-methyl-2-mercaptoimidazole in the preparation process of mercapto ionic liquid in Example 3 was replaced with 1-methylimidazole. Since ordinary ionic liquids are non-reducible, they cannot form chemical welds. Relying only on insufficient optical welds, the nodes of the silver nanowire network are high-resistance physical contacts with high initial sheet resistance. At the same time, these fragile nodes are easy to loosen or break when bent, resulting in a significant increase in resistance. In Comparative Example 2, the pretreated PET film in the flexible substrate preparation process of Example 3 was replaced with a PET film. Due to the inertness of the surface of the untreated PET film, the covalent organic framework layer grew unevenly and had poor adhesion. Although the conductivity was acceptable after photo-chemical welding, stress was concentrated at the fragile interface when bending, which caused the entire conductive layer to macroscopically peel off from the substrate, resulting in a sharp increase in resistance. In Comparative Example 3, the flexible substrate in the preparation process of the novel electrode material based on the flexible substrate in Example 3 was replaced with the modified PET film in Example 3. Since the modified PET film lacks sulfonate, the electrostatic anchoring effect with the silver nanowires is greatly weakened. When bent, the silver nanowires are easy to slip or even fall off on the surface of the covalent organic framework, the network integrity is destroyed, and the resistance stability is significantly reduced. In Comparative Example 4, the photowelding step in the preparation process of the novel electrode material based on a flexible substrate in Example 3 was removed. Due to the presence of only mild chemical welding, the strength and consistency of the silver nanowire node fusion were insufficient, resulting in a high initial sheet resistance. Furthermore, when bent, these incompletely fused nodes were weak points and failed preferentially, leading to a significant increase in resistance.

[0037] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a novel electrode material based on a flexible substrate, characterized by: The process includes the following steps: Step S1: Weigh the following raw materials by weight: 0.34-0.38 parts silver nitrate, 0.004-0.005 parts mercapto ionic liquid, 0.01-0.011 parts acetic acid, 20-22 parts deionized water, and 40-42 parts silver nanowire ethanol solution. Mix the silver nitrate, mercapto ionic liquid, acetic acid, and deionized water, and stir at room temperature for 15-20 minutes. Then add the silver nanowire solution and continue stirring for 30-40 minutes to obtain the electrode coating solution. The mass fraction of the silver nanowire ethanol solution is 0.25%. Step S2: Using a spin coater, spin coat the flexible substrate with electrode coating solution (0.8-1 mL). The temperature is room temperature. First, spin coat at 500 rpm for 20 seconds, then at 3000 rpm for 30 seconds. Repeat the spin coating 3-4 times. Then dry at 60℃ for 10-15 minutes. Finally, place under a xenon lamp at a light power density of 8 J / cm². 2 A novel electrode material based on a flexible substrate was prepared by photowelding under an irradiation time of 5 seconds.

2. The method of claim 1, wherein the method comprises: The flexible substrate is prepared by the following steps: Step A1: 2,4,6-tris(4-bromophenyl)-1,3,5-triazine and tetrahydrofuran were mixed and stirred at a stirring rate of 100-120 rpm and a temperature of -78°C. Then n-butyllithium was added and stirred for 3-4 h. N,N-dimethylformamide was then added, the temperature was raised to 25°C, and the mixture was stirred for 10-12 h. Hydrochloric acid solution was then added and stirred for 1-2 h. The mixture was then distilled under reduced pressure, extracted with chloroform, and the organic layer was washed with saturated sodium chloride solution. The mixture was then distilled under reduced pressure and dried to obtain the aldehyde intermediate. Step A2: Cut the PET film into 10cm×10cm pieces and place them in a UV ozone cleaner. Under conditions of 50% relative humidity, 30℃ temperature, 254nm UV lamp, and 250W power, perform UV ozone treatment for 8-10 minutes. Wash with deionized water and dry to obtain a pretreated PET film. Mix 4,4'-diaminobiphenyl, aldehyde intermediate, trimethylbenzene, and ethanol and ultrasonically disperse for 15-20 minutes to obtain a mixture system. Place the pretreated PET film in a container and pour in the mixture system. Let it stand for 15-20 minutes, then add acetic acid solution. React at 25℃ for 24 hours. Filter, wash, and dry to obtain a modified PET film. Step A3: Sodium 4-vinylbenzenesulfonate, 2,3-dichloro-5,6-dicyanobenzoquinone, boron trifluoride ether and N,N-dimethylformamide are mixed and ultrasonically dispersed for 10-15 min. Then, the mixture is added to a container containing a modified PET film and reacted at 80°C for 48 h. After filtration, the mixture is washed with deionized water / ethanol and dried to obtain a flexible substrate.

3. The method of claim 2, wherein the method further comprises: In step A1, the volume ratio of 2,4,6-tris(4-bromophenyl)-1,3,5-triazine, tetrahydrofuran, n-butyllithium, N,N-dimethylformamide, and hydrochloric acid solution is 6.4-6.5 g : 180-200 mL : 5.6-5.8 mL : 10-15 mL : 70-80 mL, and the mass fraction of the hydrochloric acid solution is 10%.

4. The method of claim 2, wherein the method further comprises: In step A2: the ratio of 4,4'-diaminobiphenyl, aldehyde intermediate, trimethylbenzene, ethanol, and acetic acid solution is 0.62-0.64g: 1.4-1.5g: 40-50mL: 40-50mL: 10-12mL, and the mass fraction of acetic acid solution is 40%.

5. The method of claim 2, wherein the method further comprises: In step A3: the ratio of sodium 4-vinylbenzenesulfonate, 2,3-dichloro-5,6-dicyanobenzoquinone, boron trifluoride ether and N,N-dimethylformamide is 0.8-0.9g: 0.28-0.3g: 0.4-0.42g: 30-35mL.

6. The method of claim 1, wherein the method further comprises: The thiol ionic liquid is prepared by the following steps: 1-Methyl-2-mercaptoimidazole and ethanol were mixed and stirred at 150-180 rpm and 75°C. 1,3-Propanesulfonyl lactone was added, and the mixture was reacted for 6-8 h. The mixture was filtered, washed with ethyl acetate / ether, and dried to obtain the precursor. The precursor was mixed with deionized water, stirred, and hydrochloric acid solution was added. The mixture was reacted at 150-180 rpm and 90°C for 12 h. The mixture was then distilled under reduced pressure, washed with ether, and dried to obtain the mercapto ionic liquid.

7. The method of claim 6, wherein the method further comprises: In the preparation of mercapto ionic liquids, the ratio of 1-methyl-2-mercaptoimidazole, ethanol, 1,3-propanesulfonyl lactone, deionized water and hydrochloric acid solution is 11.4-11.5g: 80-90mL: 12.2-12.3g: 30-35mL: 18-20mL, and the mass fraction of hydrochloric acid solution is 38%.

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