Flexible electrode based on silver nanowire and polyethyleneimine and preparation method thereof

Abstract

The invention discloses a flexible electrode based on silver nanowires and polyethyleneimine and a preparation method thereof, and belongs to the technical field of flexible electronic devices, and the preparation method comprises the following steps: S1, mixing polyvinylpyrrolidone, ethylene glycol, silver nitrate and sodium chloride, stirring, and purifying to obtain an AgNWs dispersion liquid; s2, mixing polyvinylpyrrolidone, isopropanol and glycerol, and violently stirring to obtain an ink solvent; s3, the AgNWs dispersion liquid is centrifuged, precipitates are taken and dissolved in an ink solvent, polyethyleneimine is added, and AgNWs conductive ink is obtained; s4, coating the AgNWs conductive ink on the substrate, and drying after coating; and S5, after coating is finished, a sample is annealed and soaked in water, and the flexible electrode based on the silver nanowires and the polyethyleneimine is obtained. According to the invention, the problem of poor conductivity of the flexible electrode caused by the fact that a thickening agent is a polymer and a modifier covers a conductive network in the prior art is solved, and the flexible electrode has the potential of being applied to preparation of flexible electronic devices.

Description

Technical Field

[0001] This invention relates to the field of flexible electronic device technology, specifically to a flexible electrode based on silver nanowires and polyethyleneimine and its preparation method. Background Technology

[0002] With the rapid development of printed electronics (PFE), it has shown broad application prospects in flexible, wearable electronic devices, and sensors. The conductivity of PFE is mainly achieved by adding different conductive fillers, which are deposited on the substrate to form conductive pathways. Among them, metal nanowires have attracted much attention due to their unique one-dimensional structure and high aspect ratio, enabling the construction of highly efficient conductive networks. Silver nanowires (AgNWs), in particular, are widely used in PFEs due to their excellent conductivity, stable mechanical properties, and chemical stability. In recent years, numerous studies have been conducted on the formulation of AgNWs-based flexible electrodes. However, most of these studies require complex post-processing steps, such as high-temperature annealing, intense pulsed light sintering (IPL), and selective laser sintering (SLS), which increases the cost and complexity of manufacturing.

[0003] Several challenges exist in the production of AgNWs flexible electrodes, primarily including the following: The high aspect ratio and low penetration threshold of AgNWs result in good dispersion at low concentrations, but IPL and SLS are needed to connect the conductive network and improve conductivity. Increasing the AgNWs concentration can improve the contact resistance and reduce the sheet resistance of the device, but it leads to uneven dispersion. Simultaneously, the low viscosity of the AgNWs ink used to prepare the flexible electrode causes disordered ink flow on the substrate, reducing the uniformity of the flexible electrode. Increasing the ink viscosity can limit this disordered ink flow, thus solving the above problem. However, traditional thickeners are polymers, which severely affect the conductivity of the silver nanowires. Furthermore, the dispersion performance of AgNWs is a major factor limiting the application of flexible electrodes. Adding glycerol and PVP can significantly improve this situation, but their small molecule characteristics can cover the AgNWs network, preventing the formation of conductive pathways. Water immersion can remove organic matter from the AgNWs network, allowing the silver wire network to form conductive pathways. However, in the formulation of inks for flexible electrodes, IPA, PVP, and glycerol are all miscible with water, which makes the AgNWs network of the flexible electrode easy to fall off after water immersion treatment.

[0004] Therefore, there is an urgent need to develop a flexible AgNWs electrode that can maintain good dispersion performance at high concentrations, requires no complicated post-processing steps, and is substrate-friendly. Summary of the Invention

[0005] Therefore, this invention provides a flexible electrode based on silver nanowires and polyethyleneimine and its preparation method, in order to solve the problem of poor conductivity of flexible electrodes in the prior art due to the thickener being a polymer and the modifier being a small molecule covering the conductive network.

[0006] To achieve the above objectives, the present invention provides the following technical solution: According to a first aspect of the present invention, a method for preparing a flexible electrode based on silver nanowires and polyethyleneimine is provided, comprising the following steps: S1. Dissolve polyvinylpyrrolidone in ethylene glycol and stir at room temperature. After dissolution, add silver nitrate to the mixture, protect from light and stir. Then, transfer the mixture to a three-necked flask, add sodium chloride solution under oil bath conditions and continue the reaction. After the reaction is complete, remove the three-necked flask and quickly cool it to room temperature in an ice-water bath. Then wash and centrifuge the mixture, and dissolve the precipitate again with deionized water to obtain AgNWs dispersion. S2. Dissolve polyvinylpyrrolidone in a mixed solvent composed of isopropanol and glycerol, and stir vigorously to obtain an ink solvent; S3. Centrifuge the AgNWs dispersion to collect the precipitate, dissolve the precipitate in ink solvent to a final concentration of 8 mg / mL and add polyethyleneimine, mix well to obtain AgNWs conductive ink. S4. Fix the polyethylene terephthalate substrate onto the working platform of the automatic coating machine, and use the Mayer rod to uniformly coat the AgNWs conductive ink onto the surface of the polyethylene terephthalate, performing one coating operation each in the transverse and longitudinal directions; after each coating is completed, immediately heat up the automatic coating machine to dry it, so as to fully evaporate the solvent components in the ink. S5. After the coating process is completed, the sample is transferred to the heating stage for annealing. The obtained sample is then immersed in water to finally obtain a flexible electrode based on silver nanowires and polyethyleneimine.

[0007] Further, the mass-to-volume ratio of polyvinylpyrrolidone, ethylene glycol, silver nitrate, and sodium chloride in step S1 is 0.6 g: 80 mL: 0.25 g: 0.12 mg.

[0008] Furthermore, the oil bath temperature in step S1 is 165°C, and the oil bath time is 70 minutes.

[0009] Further, the mass-to-volume ratio of polyvinylpyrrolidone, isopropanol, and glycerol in step S2 is 1.5 g: 40 mL: 10 mL.

[0010] Furthermore, the stirring rate in step S2 is 500 rpm, and the stirring time is 3 hours.

[0011] Further, the mass fraction of polyethyleneimine in step S3 is 0.5 wt%.

[0012] Furthermore, the centrifugation parameters in step S3 are a rotation speed of 3000 rpm and a time of 20 min.

[0013] Furthermore, the specific steps of step S4 are as follows: The polyethylene terephthalate substrate was fixed on the working platform of the automatic coating machine. The conductive ink was uniformly coated onto the polyethylene terephthalate surface using a Mayer rod. The coating rate was set to 15 mm / s and the coating temperature to 60°C. The coating operation was performed once in the horizontal direction and once in the vertical direction. After each coating was completed, the automatic coating machine was immediately heated to 120°C and dried at this temperature for 20 minutes to fully evaporate the solvent components in the ink.

[0014] Furthermore, in step S5, the heating table temperature is 120°C, the annealing time is 1 hour, and the water immersion treatment time is 15 minutes.

[0015] According to a second aspect of the present invention, a flexible electrode based on silver nanowires and polyethyleneimine prepared by the above-described preparation method is provided.

[0016] The present invention has the following advantages: This application describes a novel flexible silver nanowire (AgNWs) electrode formulated by incorporating polyethyleneimine (PEI). Polyvinylpyrrolidone (PVP) acts as a dispersant, establishing extensive hydrogen bonds that effectively bridge the initially loose PVP molecular chains into a three-dimensional cross-linked network. The flexible electrode based on silver nanowires and polyethyleneimine is fabricated using Mayer rod coating. The resulting flexible electrode, after water immersion treatment, possesses the following advantages: (1) Excellent electrothermal performance: The maximum temperature can reach 94℃ at 2.5V voltage, and the surface temperature of the flexible electrode does not fluctuate significantly after running at maximum power for more than 1 hour, showing stable electrothermal performance.

[0017] (2) Aging resistance: The sheet resistance of the prepared flexible electrode is 3.2Ω / sq, which only slightly increases to 4Ω / sq after being exposed to ambient air for one month.

[0018] (3) Excellent electromagnetic shielding performance: The flexible electrode based on silver nanowires and polyethyleneimine exhibits excellent electromagnetic shielding performance with a shielding efficiency of up to 43dB.

[0019] (4) Simple preparation process: The entire process can be completed at room temperature and pressure. It is simple and efficient to operate and has strong environmental adaptability, making it suitable for large-scale preparation. Attached Figure Description

[0020] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0021] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0022] Figure 1 The process flow diagram for fabricating the IP-AgNWs flexible electrode prepared according to the present invention is shown. Figure 2 Optical images of the P-AgNWs and AgNWs flexible electrodes prepared for this invention after water immersion treatment; Figure 3 SEM morphology image of the P-AgNWs flexible electrode prepared according to the present invention; Figure 4 SEM morphology image of the IP-AgNWs flexible electrode prepared according to the present invention; Figure 5 Time-temperature curves of the IP-AgNWs flexible electrode prepared for this invention at voltages of 0.5-2.5V; Figure 6 Cyclic electroheating curve of the IP-AgNWs flexible electrode prepared for this invention at 2.5V; Figure 7 Time-temperature curve of the IP-AgNWs flexible electrode prepared for this invention operating at 2.5V for 1 hour; Figure 8 The diagram shows the overall electromagnetic shielding efficiency of the IP-AgNWs flexible electrode prepared according to the present invention. Detailed Implementation

[0023] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] According to a first aspect of the present invention, a method for preparing a flexible electrode based on silver nanowires and polyethyleneimine is provided, comprising the following steps: S1. Dissolve polyvinylpyrrolidone in ethylene glycol and stir at room temperature. After dissolution, add silver nitrate to the mixture, protect from light and stir. Then, transfer the mixture to a three-necked flask, add sodium chloride solution under oil bath conditions and continue the reaction. After the reaction is complete, remove the three-necked flask and quickly cool it to room temperature in an ice-water bath. Then wash and centrifuge the mixture, and dissolve the precipitate again with deionized water to obtain AgNWs dispersion. S2. Dissolve polyvinylpyrrolidone in a mixed solvent composed of isopropanol and glycerol, and stir vigorously to obtain an ink solvent; S3. Centrifuge the AgNWs dispersion to collect the precipitate, dissolve the precipitate in ink solvent to a final concentration of 8 mg / mL and add polyethyleneimine, mix well to obtain AgNWs conductive ink. S4. Fix the polyethylene terephthalate substrate onto the working platform of the automatic coating machine, and use the Mayer rod to uniformly coat the AgNWs conductive ink onto the surface of the polyethylene terephthalate, performing one coating operation each in the transverse and longitudinal directions; after each coating is completed, immediately heat up the automatic coating machine to dry it, so as to fully evaporate the solvent components in the ink. S5. After the coating process is completed, the sample is transferred to the heating stage for annealing. The obtained sample is then immersed in water to finally obtain a flexible electrode based on silver nanowires and polyethyleneimine.

[0025] In step S1, the mass-to-volume ratio of polyvinylpyrrolidone, ethylene glycol, silver nitrate, and sodium chloride is 0.6 g: 80 mL: 0.25 g: 0.12 mg.

[0026] In step S1, the oil bath temperature is 165℃ and the oil bath time is 70min.

[0027] In step S2, the mass-to-volume ratio of polyvinylpyrrolidone, isopropanol, and glycerol is 1.5 g: 40 mL: 10 mL.

[0028] In step S2, the stirring rate is 500 rpm and the stirring time is 3 hours.

[0029] In step S3, the mass fraction of polyethyleneimine is 0.5 wt%.

[0030] In step S3, the centrifugation parameters are 3000 rpm and 20 min.

[0031] The specific steps of step S4 are as follows: The polyethylene terephthalate substrate was fixed on the working platform of the automatic coating machine. The conductive ink was uniformly coated onto the polyethylene terephthalate surface using a Mayer rod. The coating rate was set to 15 mm / s and the coating temperature to 60°C. The coating operation was performed once in the horizontal direction and once in the vertical direction. After each coating was completed, the automatic coating machine was immediately heated to 120°C and dried at this temperature for 20 minutes to fully evaporate the solvent components in the ink.

[0032] In step S5, the heating table temperature is 120℃, the annealing time is 1 hour, and the water immersion treatment time is 15 minutes.

[0033] According to a second aspect of the present invention, a flexible electrode based on silver nanowires and polyethyleneimine prepared by the above-described preparation method is provided.

[0034] To better illustrate the performance of the flexible electrode based on silver nanowires and polyethyleneimine prepared according to the present invention, the following examples and test cases are provided.

[0035] Example 1 A method for fabricating a flexible electrode based on silver nanowires and polyethyleneimine, the fabrication process is as follows: Figure 1 As shown, it includes the following steps: S1. Dissolve 0.6 g of polyvinylpyrrolidone (PVP) in 80 mL of ethylene glycol (EG) and stir at room temperature. After dissolution, add 0.25 g of silver nitrate to the mixture, stir while protecting from light, and then transfer the mixture to a three-necked flask. Under oil bath conditions at 165 °C, add 2.1 μL of 1 mol / L NaCl solution and continue the reaction for 70 min. After the reaction is complete, remove the three-necked flask and quickly cool it to room temperature in an ice-water bath. Then, wash and centrifuge the mixture, and dissolve the precipitate again with deionized water to obtain an AgNWs dispersion. S2. Dissolve 1.5g of PVP in a mixed solvent consisting of 40mL of isopropanol (IPA) and 10mL of glycerol (GI), and stir vigorously for 3 hours to obtain the ink solvent; S3. Centrifuge the AgNWs dispersion to collect the precipitate, dissolve the precipitate in ink solvent to a final concentration of 8 mg / mL and add 0.5 wt% polyethyleneimine. Mix well to obtain AgNWs conductive ink. S4. Fix the PET substrate on the working platform of the automatic coating machine. Use the Mayer rod to uniformly coat the conductive ink onto the PET surface at a coating rate of 15 mm / s. Perform one coating operation in both the transverse and longitudinal directions. After each coating is completed, immediately heat the automatic coating machine to 120°C and dry it at this temperature for 20 minutes to fully evaporate the solvent components in the ink. S5. After the coating process is completed, the sample is transferred to the heating stage and annealed at 120°C for 1 hour. Then, the sample is immersed in water for 15 minutes to obtain the IP-AgNWs flexible electrode.

[0036] Example 2 The method for preparing AgNWs flexible electrodes includes the following steps: S1. Dissolve 0.6 g of polyvinylpyrrolidone (PVP) in 80 mL of ethylene glycol (EG) and stir at room temperature. After dissolution, add 0.25 g of silver nitrate to the mixture, stir while protecting from light, and then transfer the mixture to a three-necked flask. Under oil bath conditions at 165 °C, add 2.1 μL of 1 mol / L NaCl solution and continue the reaction for 70 min. After the reaction is complete, remove the three-necked flask and quickly cool it to room temperature in an ice-water bath. Then, wash and centrifuge the mixture, and dissolve the precipitate again with deionized water to obtain an AgNWs dispersion. S2. Dissolve 1.5g of PVP in 50mL of a mixed solvent composed of glycerol (GI) and stir vigorously for 3h to obtain an ink solvent; S3. Centrifuge the AgNWs dispersion to collect the precipitate, dissolve the precipitate in ink solvent to a final concentration of 8 mg / mL and add 0.5 wt% polyethyleneimine. Mix well to obtain AgNWs conductive ink. S4. Fix the PET substrate on the working platform of the automatic coating machine. Use the Mayer rod to uniformly coat the conductive ink onto the PET surface at a coating rate of 15 mm / s. Perform one coating operation in both the transverse and longitudinal directions. After each coating is completed, immediately heat the automatic coating machine to 120°C and dry it at this temperature for 20 minutes to fully evaporate the solvent components in the ink. S5. After the coating process is completed, the sample is transferred to a heating stage and annealed at 120°C for 1 hour to obtain AgNWs flexible electrode.

[0037] Example 3 The method for preparing P-AgNWs flexible electrodes includes the following steps: S1. Dissolve 0.6 g of polyvinylpyrrolidone (PVP) in 80 mL of ethylene glycol (EG) and stir at room temperature. After dissolution, add 0.25 g of silver nitrate to the mixture, stir while protecting from light, and then transfer the mixture to a three-necked flask. Under oil bath conditions at 165 °C, add 2.1 μL of 1 mol / L NaCl solution and continue the reaction for 70 min. After the reaction is complete, remove the three-necked flask and quickly cool it to room temperature in an ice-water bath. Then, wash and centrifuge the mixture, and dissolve the precipitate again with deionized water to obtain an AgNWs dispersion. S2. Dissolve 1.5g of PVP in a mixed solvent consisting of 40mL of isopropanol (IPA) and 10mL of glycerol (GI), and stir vigorously for 3 hours to obtain the ink solvent; S3. Centrifuge the AgNWs dispersion to collect the precipitate, dissolve the precipitate in ink solvent to a final concentration of 8 mg / mL and add 0.5 wt% polyethyleneimine. Mix well to obtain AgNWs conductive ink. S4. Fix the PET substrate on the working platform of the automatic coating machine. Use the Mayer rod to uniformly coat the conductive ink onto the PET surface at a coating rate of 15 mm / s. Perform one coating operation in both the transverse and longitudinal directions. After each coating is completed, immediately heat the automatic coating machine to 120°C and dry it at this temperature for 20 minutes to fully evaporate the solvent components in the ink. S5. After the coating process is completed, the sample is transferred to a heating stage and annealed at 120°C for 1 hour to obtain the P-AgNWs flexible electrode.

[0038] Example 4 This embodiment is based on Embodiment 1, except that the concentration of AgNWs in step S3 is 3 mg / mL, and the other specific processing parameters are the same as in Embodiment 1, resulting in the IP-AgNWs flexible electrode A3.

[0039] Example 5 This embodiment is based on Embodiment 1, except that the concentration of AgNWs in step S3 is 4 mg / mL, and the other specific processing parameters are the same as in Embodiment 1, resulting in the IP-AgNWs flexible electrode A4.

[0040] Example 6 This embodiment is based on Embodiment 1, except that the concentration of AgNWs in step S3 is 5 mg / mL, and the other specific processing parameters are the same as in Embodiment 1, to obtain the IP-AgNWs flexible electrode A5.

[0041] Example 7 This embodiment is based on Embodiment 1, except that the concentration of AgNWs in step S3 is 6 mg / mL, and the other specific processing parameters are the same as in Embodiment 1, resulting in the IP-AgNWs flexible electrode A6.

[0042] Example 8 This embodiment is based on Embodiment 1, except that the concentration of AgNWs in step S3 is 7 mg / mL, and the other specific processing parameters are the same as in Embodiment 1, resulting in the IP-AgNWs flexible electrode A7.

[0043] Test Example 1 P-AgNWs flexible electrodes and AgNWs flexible electrodes, each measuring 5cm×5cm, were fixed to the bottom of a petri dish. The center of their surfaces was secured with double-sided tape. 20mL of deionized water was slowly poured into the petri dish from the edge, immersing the flexible electrodes for 10min. Time and images of surface changes on the flexible electrodes were recorded every 2min.

[0044] like Figure 2 As shown, the AgNWs flexible electrode completely dissolved within 10 minutes, while the P-AgNWs flexible electrode remained almost undissolved. This indicates that the addition of PEI significantly improved the chemical stability of the P-AgNWs flexible electrode in the aqueous environment and effectively resisted the penetration of water molecules.

[0045] Test Example 2 The surface morphology of the prepared flexible electrode was characterized by field emission scanning electron microscopy (SEM).

[0046] like Figure 3 As shown in the SEM morphology image of the P-AgNWs flexible electrode prepared in Example 3, the AgNWs are linear with clear edges and good dispersion. The ink tightly coats or bridges the AgNWs network, making the AgNWs network more fully connected and locally smoothed, but tiny particles are attached to the surface of the AgNWs network. Figure 4 The SEM morphology image of the IP-AgNWs flexible electrode prepared in Example 1 shows that the tiny particles attached to the surface of its AgNWs network were completely removed by water immersion, and the surface was relatively smooth; the AgNWs network structure was obvious.

[0047] Test Example 3 A flexible IP-AgNWs electrode measuring 3cm × 1.5cm was fixed to a thermally insulating ceramic substrate. A thermocouple was fixed to the center of the substrate with high-temperature tape, and the edges were connected with four-probe electrodes (1.5mm spacing) from a Keithley 2700 resistance meter. The voltage was set to 0.5V, 1V, 1.5V, 2V, and 2.5V, and an "on-off" cycle was used. The thermocouple recorded the temperature every 1 second, and the time (s) and temperature (°C) were recorded simultaneously.

[0048] from Figure 5 The electroheating curves of the IP-AgNWs flexible electrode prepared in Example 1, shown in the figure, indicate that the IP-AgNWs flexible electrode reaches a maximum steady-state temperature of approximately 94°C at a low voltage of 2.5V. From... Figure 6 The cyclic electroheating curve of the IP-AgNWs flexible electrode prepared in Example 1 at 2.5V shows that the flexible electrode reaches a maximum steady-state temperature of approximately 94℃ at a low voltage of 2.5V, and the cyclic curve exhibits relatively small fluctuations. Figure 7The long-term heating curve of the IP-AgNWs flexible electrode prepared in Example 1 at 2.5V shows that the highest steady-state temperature of the flexible electrode reaches about 94°C at a low voltage of 2.5V, and the electrothermal performance of the flexible electrode remains stable after a long heating period of 1 hour. This indicates that the IP-AgNWs flexible electrode has excellent electrothermal performance.

[0049] Test Example 4 The IP-AgNWs flexible electrodes prepared in Examples 1 and 4-8 were cut into strips of 3cm × 3cm and placed in a vector network analyzer (Agilent-E5071C) to test the electromagnetic interference (EMI) shielding performance of the IP-AgNWs flexible electrodes in the frequency range of 8.2-12.4GHz using the waveguide method.

[0050] Figure 8 The diagram shows the total electromagnetic shielding efficiency of the IP-AgNWs flexible electrode prepared according to the present invention. It can be seen that the reaction effect, absorption effect, and total shielding effect of the IP-AgNWs flexible electrodes prepared in Example 1 (sample A8) and Examples 4-8 increase with the increase of AgNWs dosage. The IP-AgNWs flexible electrode prepared in Example 1 exhibits a total shielding effect as high as 43 dB in the frequency range of 8.2-12.4 GHz.

[0051] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for preparing a flexible electrode based on silver nanowires and polyethyleneimine, comprising the following steps: S1, dissolving polyvinylpyrrolidone in ethylene glycol and stirring at room temperature; after dissolving, adding silver nitrate into the mixed solution, avoiding light and stirring; then, transferring the mixed solution to a three-necked flask, adding sodium chloride solution under oil bath condition and continuing the reaction; after the reaction is completed, taking out the three-necked flask and rapidly cooling to room temperature with an ice water bath, and then performing washing and centrifugal treatment, dissolving the precipitate with deionized water again to obtain an AgNWs dispersion; S2, dissolving polyvinylpyrrolidone in a mixed solvent composed of isopropyl alcohol and glycerol and obtaining an ink solvent by vigorous stirring; S3, centrifuging the AgNWs dispersion to obtain a precipitate, dissolving the precipitate in the ink solvent to a final concentration of 8 mg / mL and adding polyethyleneimine, and uniformly mixing to obtain an AgNWs conductive ink; S4, fixing a polyethylene terephthalate substrate on a working platform of an automatic film coating machine, uniformly coating the AgNWs conductive ink on the surface of the polyethylene terephthalate using a Meyer rod, and performing coating operation once along the transverse direction and the longitudinal direction respectively; after each coating is completed, immediately heating the automatic film coating machine to dry, so as to sufficiently volatilize the solvent components in the ink; S5, after the coating process is completed, transferring the sample to a heating table to perform annealing treatment, and performing water immersion treatment on the prepared sample, to finally obtain a flexible electrode based on silver nanowires and polyethyleneimine.

2. The method for preparing a flexible electrode based on silver nanowires and polyethyleneimine according to claim 1, characterized in that, In step S1, the mass-volume ratio of the polyvinylpyrrolidone, ethylene glycol, silver nitrate and sodium chloride is 0.6 g:80 mL:0.25 g:0.12 mg.

3. The method for preparing a flexible electrode based on silver nanowires and polyethyleneimine as described in claim 1, characterized in that, In step S1, the oil bath temperature is 165℃, and the oil bath time is 70 min.

4. The method for preparing a flexible electrode based on silver nanowires and polyethyleneimine as described in claim 1, characterized in that, In step S2, the mass-volume ratio of the polyvinylpyrrolidone, isopropyl alcohol and glycerol is 1.5 g:40 mL:10 mL.

5. The method for preparing a flexible electrode based on silver nanowires and polyethyleneimine as described in claim 1, characterized in that, In step S2, the stirring rate is 500 rpm, and the stirring time is 3 h.

6. The method for preparing a flexible electrode based on silver nanowires and polyethyleneimine as described in claim 1, characterized in that, In step S3, the mass fraction of the polyethyleneimine is 0.5 wt%.

7. The method for preparing a flexible electrode based on silver nanowires and polyethyleneimine as described in claim 1, characterized in that, In step S3, the centrifugal parameters are a rotation speed of 3000 rpm and a time of 20 min.

8. The method for preparing a flexible electrode based on silver nanowires and polyethyleneimine as described in claim 1, characterized in that, Step S4 specifically comprises the following steps: fixing a polyethylene terephthalate substrate on a working platform of an automatic film coating machine, uniformly coating the conductive ink on the surface of the polyethylene terephthalate using a Meyer rod, setting a coating rate of 15 mm / s and a coating temperature of 60℃, and performing coating operation once along the transverse direction and the longitudinal direction respectively; after each coating is completed, immediately heating the automatic film coating machine to 120℃, and drying at this temperature for 20 min, so as to sufficiently volatilize the solvent components in the ink. 9.The method of claim 1, wherein the silver nanowire and polyethylene imine-based flexible electrode is prepared by the steps of: coating a silver nanowire dispersion solution on a substrate to form a silver nanowire layer; and coating a polyethylene imine layer on the silver nanowire layer. In step S5, the heating table temperature is 120℃, the annealing time is 1 h, and the water immersion treatment time is 15 min. 10.A flexible electrode based on silver nanowires and polyethyleneimine prepared by the method according to any one of claims 1-9.

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