A fully dry supercapacitor based on GO-PVA dry gel electrolyte, its preparation method and application

Abstract

This invention discloses a fully dry supercapacitor based on GO-PVA dry gel electrolyte, its preparation method, and its application. Polyaniline electrodes are directly grown on both sides of the GO-PVA gel electrolyte through in-situ polymerization, forming an integrated sandwich structure device with a tight electrode-electrolyte bond. After pressing and drying, a PANI / GO-PVA / PANI device with a continuous hydrogen bond network proton hopping transport channel is obtained. The supercapacitor obtained by this invention exhibits strong interfacial bonding, with a tensile strength of 3.2 MPa and a tensile strain of 475% after the introduction of a glucose modifier. It can simultaneously complete charging and discharging during repeated stretching processes. The PANI / GO-PVA / PANI flexible all-solid-state supercapacitor achieves a tensile strength of 1 mA / cm². 2 The initial specific capacitance at room temperature in a dry environment under the given current density is 877.5 mF / cm. 2 After 32 days of completely open storage, the capacitance retention rate exceeded 93.7%, and even after 6 months of storage under these conditions, the capacitance retention rate was still 92.6%. At a low temperature of -30°C, the specific capacitance remained at approximately 715 mF·cm. ‑2 It also exhibits the same mechanical properties at -30°C as at room temperature.

Description

Technical Field

[0001] This invention belongs to the field of flexible electronic devices, specifically relating to a fully dry supercapacitor based on GO-PVA dry gel electrolyte, its preparation method, and its application. Background Technology

[0002] The rapid proliferation of flexible electronics has increased the demand for energy storage systems that combine excellent mechanical and electrochemical properties. Flexible all-solid-state supercapacitors offer a promising solution; however, liquid and hydrogel electrolytes have significant drawbacks: they inevitably leak or seep out when the energy storage device deforms under stress; liquids and hydrogels have poor resistance to drying and freezing because the liquid evaporates or crystallizes, leading to a severe decrease in energy storage performance or device failure, and crystallization also makes the entire device brittle. Furthermore, as liquid components, their ion transport is affected by viscosity changes and operating conditions. Even if modifiers are introduced or other liquids are used to replace water to prevent freezing at low temperatures, increased viscosity still reduces ionic conductivity. Although they do not volatilize under dry conditions, they still rely on the liquid phase environment for conduction. External stress and repeated charge-discharge cycles promote liquid migration, creating relatively depleted liquid regions, thus reducing ionic conductivity. Currently, only inorganic ceramic solid electrolytes (sulfide and oxide-based) are used in lithium-ion batteries, but these inorganic ceramic electrolytes are not suitable for supercapacitors. Current theoretical and experimental research has only predicted or explored achieving anhydrous proton conduction by replacing water with other liquids, but has not truly achieved completely liquid-free proton conduction. In other words, a completely dry solid electrolyte for supercapacitors does not currently exist, because existing solid electrolytes used in supercapacitors would lose their ionic conductivity if completely dried. Summary of the Invention

[0003] This invention provides a fully dry supercapacitor based on GO-PVA dry gel electrolyte, its preparation method, and its application. PANI is polymerized in situ on the surface of the GO-PVA-glucose (GLU) gel electrolyte, resulting in a device with high areal capacitance and volumetric capacitance (835.0 mF·cm⁻¹). -2 and 17.8 F·cm -3 It is ultra-thin (0.4±0.05 mm thick), extremely small in size (no additional packaging required), can be stretched and folded at will, has high tensile strength, large tensile deformation, excellent mechanical stability, electrochemical cycle stability and high energy / power density, high conductivity and low impedance, and can be used in the field of new wearable flexible electronic materials.

[0004] To achieve the above objectives, the technical solution adopted by the present invention includes the following steps:

[0005] A fully dry supercapacitor based on GO-PVA dry gel electrolyte, wherein the capacitor is a device with a PANI / GO-PVA / PANI sandwich structure and the device thickness is 0.43~0.55 mm; GO-PVA is a gel electrolyte, and PANI is a polyaniline electrode with a network porous structure formed by in-situ polymerization on both sides of the electrolyte. Efficient proton channels are formed in the GO-PVA electrolyte and at the interface between it and the PANI electrode through a network of interconnected hydrogen bonds.

[0006] Optionally, GO and PVA are used as raw materials. After mixing and freezing and thawing, a pre-formed GO-PVA gel electrolyte is prepared. After being immersed in an aniline solution, polyaniline electrodes are directly grown on both sides of the pre-formed GO / PVA gel electrolyte through in-situ polymerization. After pressing and drying, a PANI / GO-PVA / PANI device with a continuous hydrogen bond network proton hopping transport channel is obtained. The amount of GO added was 0–5 mg / mL, the concentration of aniline solution was 0.2–0.5 mol / L, and the amount of PVA added was 10 wt%.

[0007] Optionally, the GO is GO nanosheets with a size of 100 nm to 3 μm, irregular edges, and obvious wrinkles on the surface of the sheets.

[0008] Optionally, the polymerization temperature of the in-situ polymerization is not higher than 4°C, and after rapid stirring for the first hour, it is allowed to stand for 8 hours to completely polymerize. The pressing and drying process involves drying for 48 hours under ambient ventilation conditions.

[0009] A fully dry supercapacitor based on GO-PVA dry gel electrolyte is obtained by introducing GLU to create pores in the PANI / GO-PVA / PANI sandwich structure of any of the fully dry supercapacitors based on GO-PVA dry gel electrolyte described in this invention, resulting in a GLU-modified PANI / GO-PVA / PANI sandwich structure dry gel flexible all-solid-state supercapacitor.

[0010] Optionally, a GO-PVA-GLU gel is prepared, and a PANI electrode is formed by in-situ polymerization on the gel surface; The preparation process includes: dispersing GO in water at a mass ratio of 0-5 mg / mL to prepare a suspension, adding 0-2 g of glucose, heating and stirring to form a GO-PVA-GLU sol with PVA, repeatedly freezing and thawing 3-4 times to obtain an electrolyte, dialyzing out GLU in water, then soaking in an aniline solution overnight, and adding APS to initiate polymerization.

[0011] Optionally, the freeze-thaw cycle is repeated by freezing at -25°C for 1 hour and thawing for 15 minutes.

[0012] Optionally, the GO-PVA-GLU electrolyte gel is soaked in an aniline solution for more than 8 hours; then, polymerization is initiated by adding an oxidant APS solution at a temperature of 0–4 °C at a rate of 3 drops per second, while the system is rapidly stirred.

[0013] Optionally, the preparation of the aniline solution includes: 1.1 ml of sulfuric acid, 0.744 g of aniline monomer, and 18.9 ml of water, to prepare a pale yellow and clear solution; The preparation of the APS solution includes: 1.1 ml of sulfuric acid, 18.9 ml of water, and APS prepared into a clear solution; The aniline monomer solution has a concentration ≥99.5% and a density of 1.022 g / cm³. 3 The sulfuric acid concentration is 98% and the density is 1.84 g / cm³.

[0014] The fully dry supercapacitor based on GO-PVA dry gel electrolyte described in this invention is used for the preparation of wearable flexible electronic materials.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The device of the present invention achieves proton conduction under completely liquid-free conditions, breaking through the bottleneck that previous capacitors could not conduct ions under liquid-free conditions. It has good electrochemical performance and adaptability to harsh environments. The supercapacitor prepared has a high areal capacitance of 835.0 mF·cm. -2 And because it does not require additional packaging, it has a high volumetric capacitance of 17.8 F·cm⁻¹. -3 The PANI / GO-PVA / PANI flexible all-solid-state supercapacitor overcomes the rate performance problem of flexible supercapacitors, achieving a rate capability starting from 0.2 mA·cm⁻¹. -2 up to 5 mA·cm -2 It retains 98.5% of its areal capacitance at 25 times the current density; at 1 mA / cm² 2 The initial specific capacitance at room temperature in a dry environment under the given current density is 877.5 mF / cm. 2 After 32 days of completely open storage, the capacitance retention rate exceeded 93.7%, and even after 6 months of storage under these conditions, the capacitance retention rate was still 92.6%. At a low temperature of -30℃, the specific capacitance remained at approximately 715 mF·cm. -2 It exhibits the same mechanical properties at -30°C as at room temperature. Activation energy Ea = 0.175 eV.

[0016] (2) In this invention, PANI is grown in situ on the surface and near the surface of GO-PVA-GLU gel. While obtaining a high PANI loading, the electrode and electrolyte are tightly bonded. It has a tensile strength of 3.2 MPa (475% strain) and can be bent and folded at will. During repeated stretching and rebounding 10,000 times, the electrode and electrolyte always maintain good bonding without peeling and retain 67% of its initial capacitance. (3) The prepared dry gel flexible all-solid supercapacitor has a connected hydrogen bond network. The shrinkage caused by the compression pressure and the capillary force after the water evaporates can shrink the device from a thickness of 3.5 mm to only 0.43~0.55 mm. The device preparation process is simple, easy to industrialize, and can be cut into different shapes to meet production needs.

[0017] (4) The PANI / GO-PVA-GLU / PANI dry-state dual-gel flexible all-solid-state supercapacitor prepared in this invention has a high ionic conductivity of 6.23 mS·cm at -30℃. -1 Furthermore, the tensile strength and tensile curve at this temperature are similar to those at room temperature. (5) In this invention, an appropriate GLU content of 1 g / 10 mL is used to create pores in the electrolyte of the device and then polymerize it. The GLU occupies the space in the electrolyte. After the GLU is dialyzed out, polyaniline is polymerized. At this time, the polymerized polyaniline is not only on the surface, but also in the deep part to form a PVA / PANI double gel network to obtain higher loading and cycling stability. Furthermore, PANI provides more protons and improves ion conductivity. The dried gel electrolyte has a strong fixation effect on PANI and can significantly inhibit PANI aggregation and the formation of long-range conductive networks. The system is more likely to exist in the form of a large number of micro capacitors rather than a continuous conductive path. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. Supercapacitors using GLU-modified GO-PVA dry gel electrolyte are named PANI / GO-PVA-GLU / PANI, and supercapacitors without GLU are named PANI / GO-PVA / PANI, where " / " represents the interface between the electrolyte and the electrode, and "-" represents the interface between different phases in the electrolyte. In the accompanying drawings; Figure 1The following are scanning electron microscope images of the present invention: Figures a and b are cross-sections of the PANI / GO-PVA / PANI (excluding GLU) flexible all-solid-state supercapacitor after compression drying, and Figures c and d are cross-sections of the freeze-dried (uncompressed) device; Figure 2 The following are optical microscopic images of the present invention at different GLU concentrations: Figure a shows the device without GLU, and Figures b, c and d show the device with 1 g / 10 ml GLU added. Figures b to d show the morphology of the device when the aniline concentration is 0.4, 0.5 and 0.6 mol / L. Figure 3 This is a demonstration of the thickness of the invention; Figure 4 Transmission electron microscope images of the GO of the present invention: Figures a and b show the size and number of layers of GO; Figure 5 Macroscopic images of the PANI / GO-PVA / PANI dry-state dual-gel flexible all-solid-state supercapacitor prepared in this invention; Figures a and b show the device bent and folded into different shapes. Figure 6 Figure 1 shows the mechanical performance test results of the present invention; Figure 2 shows the discharge of the PANI / GO-PVA / PANI dry-state dual-gel flexible all-solid-state supercapacitor under repeated stretching and compression; Figure 3 shows the tensile strength of the PANI / GO-PVA-GLU / PANI device (the PANI / GO-PVA / PANI device is the one with 0 GLU added) under different GLU concentrations; Figure 4 shows the comparison of the PANI / GO-PVA / PANI device after 10,000 stretching and compression cycles. Figure 7 Figure 1 shows the electrochemical performance of PANI / GO-PVA / PANI supercapacitors with different GO concentrations prepared in this invention. No GLU was added, and the supercapacitors were prepared using GO-PVA gel. Figure 2a is a bar chart of the area specific capacitance calculated from the GCD curves of devices with different GO contents; Figure 3b is an EIS diagram of devices with different GO contents; Figure 4c is a GCD curve of the device prepared with a 2 mg / mL GO concentration at different current densities. Figure 8 For the PANI / GO-PVA-GLU / PANI device of this invention, different concentrations of aniline monomer were used for polymerization, and the device was prepared by adding 1 g / 10 mL of glucose. Electrochemical performance test results are shown in Figure a: Figure a shows the device at 1 mA·cm⁻¹. -2 Figure b shows the GCD plot of the device at current density; Figure b shows the device at 10 mV·s. -1 CV plot at scan rate; Figure 9Figure a shows a comparison of the optimal electrochemical performance samples of the PANI / GO-PVA / PANI device and the PANI / GO-PVA-GLU / PANI device of this invention; Figure a shows the device at 1 mA·cm -2 Figure b shows the GCD plot of the device at current density; Figure b shows the device at 10 mV·s. -1 CV plot at scan rate; Figure 10 Figure a shows the rate performance test results of the PANI / GO-PVA-GLU / PANI device of this invention; Figure a shows the rate performance test results at different current densities (1 mA·cm). -1 Figure 1 shows the GCD curve; Figure 2 shows the CV curves at different scan rates; Figure 11 Figure 1 shows the electrochemical performance changes of the PANI / GO-PVA-GLU / PANI device of the present invention after different drying times; Figure 2a shows the electrochemical performance changes at 1 mA·cm⁻¹ after different drying times. -1 Figure 1 shows the discharge curves of the device at the given current density; Figure 2b shows the discharge curves after drying for different times at 10 mV·s. -1 CV curves of the device at different scanning speeds; Figure 12 The curves show the changes in the areal capacitance of the PANI / GO-PVA-GLU / PANI device of the present invention after different drying times. Figure 13 The curves showing the changes in areal capacitance and coulombic efficiency of the PANI / GO-PVA-GLU / PANI device of the present invention after 2100 charge-discharge cycles are shown. Figure 14 Figure 1 shows the performance changes of the PANI / GO-PVA-GLU / PANI device of the present invention at extreme low temperatures; Figure 2 shows the changes in GCD curves at 25℃, 0℃, -10℃, -20℃, and -30℃; Figure 3 shows the changes in CV curves at 25℃, 0℃, -10℃, -20℃, and -30℃; Figure 4 shows the changes in EIS curves at 25℃, 0℃, -10℃, -20℃, and -30℃; Figure 5 shows the activation energy calculated by linear fitting of ionic conductivity. Figure 15 The CV curves of the PANI / GO-PVA / PANI device of this invention were tested at different scan rates after drying for 6 months.

[0019] Figure 16 To demonstrate the low-temperature resistance of the PANI / GO-PVA / PANI device (without added glucose) of this invention, Figure a shows the CV curves at different temperatures, Figure b shows the impedance spectra at different temperatures, Figure c shows the calculated activation energy of the device, and Figure d shows the stretching curves at low temperature and at room temperature.

[0020] Figure 17 To illustrate the drought resistance of the PANI / GO-PVA / PANI device (without added glucose) of this invention, the black dotted line represents relative humidity, while the bar chart represents the area-to-capacitance ratio.

[0021] Figure 18 The curves obtained from the thermogravimetric analysis of the PANI / GO-PVA / PANI device (without glucose) of this invention are shown. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only a part of the embodiments of the present invention, not all of them, and do not impose any limitations on the present invention. Any use of the technical solutions of this embodiment, including simple modifications to this embodiment, falls within the scope of protection of the present invention.

[0023] This invention relates to a fully dry supercapacitor based on GO-PVA dry gel electrolyte, its preparation method, and its application. GO and PVA are mixed and freeze-thawed to obtain a GO-PVA hydrogel. Polyaniline electrodes are directly grown on both sides of the pre-formed GO-PVA gel electrolyte through in-situ polymerization, forming an integrated sandwich structure device with a tight electrode-electrolyte bond. After pressing and drying, a PANI / GO-PVA / PANI device with a continuous hydrogen bond network and proton hopping transport channels is obtained. The supercapacitor obtained by this invention exhibits strong interfacial bonding, a tensile strength of 2.8 MPa, and a tensile strain of 221%. After introducing a glucose modifier, the tensile strength reaches 3.2 MPa, and the tensile strain reaches 475%. It can simultaneously complete charge and discharge during repeated stretching processes, demonstrating excellent mechanical stability. The PANI / GO-PVA / PANI flexible all-solid-state supercapacitor achieves a speed of 1 mA / cm². 2 The initial specific capacitance at room temperature in a dry environment under the given current density is 877.5 mF / cm. 2 After 32 days of completely open storage, the capacitance retention rate exceeded 93.7%, and even after 6 months of storage under these conditions, the capacitance retention rate was still 92.6%. At a low temperature of -30℃, the specific capacitance remained at approximately 715 mF·cm. -2 It also exhibits the same mechanical properties at -30℃ as at room temperature.

[0024] The composite aerogel electrode material of this invention includes a thicker PVA / PANI dual-gel network obtained by doping and then dialysis with GLU, and the construction of a GO-PVA gel with a large number of compact hydrogen bond networks by utilizing the capillary force brought about by water evaporation to achieve anhydrous proton conduction using the Grotthuss mechanism. The method of integrated fabrication of electrodes and electrolytes for supercapacitors involves directly growing PANI in situ on the surface. During the air-drying process, a large number of hydrogen bonds are formed not only in the electrolyte gel but also at the interface, ultimately forming a complete proton hopping path in the device. However, during cycling, PANI undergoes repeated ion insertion / extraction, leading to volume expansion. Integrated device fabrication methods often lack suitable solutions to this volume expansion problem because it is difficult to introduce carbon materials or fabricate dual-gel networks with higher cycling stability using normal methods. This invention proposes a new method for forming dual-gel networks using a GLU-doped pore-forming process. The interlocking of PVA and polyaniline provides space for volume expansion and higher cycling stability. This device has a three-dimensional porous mesh structure. After air drying, the pore size becomes smaller and the thickness becomes very thin, which makes the ion transport distance very short. After drying, PANI and sulfate can act as ion sources to provide dissociated protons, which is necessary for the usability of the device after drying. In addition, GO has excellent conductivity and can also provide ion conduction capability, becoming a "highway" on the proton hopping path.

[0025] Specifically, GO / PVA gel electrolyte was prepared using GO, PVA, and GLU as raw materials. The optimal addition amount of GO suspension (1#GO suspension) was 2 mg / mL, the optimal addition mass fraction of PVA was 10%, and the optimal addition amount of GLU was 1 g / 10ml. The prepared GO-PVA-GLU hydrogel had a size of 20mm×20mm×3mm. After dialysis, the size will increase slightly. Finally, GLU needs to be dialyzed out of the hydrogel with water, which requires more than three water changes for dialysis.

[0026] Finally, the device is immersed in a high concentration of aniline monomer solution. The optimal addition amount of aniline monomer is 0.5 mol / L. The immersion time is more than 8 h to ensure that the aniline monomer can be pumped into the electrolyte by the concentration difference, so that a PVA / PANI double gel network can be polymerized. The thickness of the PANI layer is about 1 mm, and the thickness of the GO / PVA double gel layer is 0.5 mm. After drying and shrinking, the thickness of the device is 0.4 ± 0.05 mm. The GO sheet is a few layers or even a single layer, and the diameter of the GO sheet is widely distributed, ranging from 100 nm to 3 μm.

[0027] The preparation of the PANI / GO-PVA-GLU / PANI dry-state dual-gel flexible all-solid-state supercapacitor includes: 2 mg / mL GO, 10% PVA, and 1 g / 10 mL GLU are stirred at above 80°C until completely dissolved. The resulting GO-PVA-GLU sol is placed in a 20 mm × 20 mm × 3 mm mold and frozen at -20°C for 1 h followed by thawing for 15 min, undergoing repeated freeze-thaw cycles to obtain a solid gel. The gel is then dialyzed against GLU three times in water to obtain the GO-PVA-GLU gel. This gel is then immersed in 20 mL of a 1 mol / L sulfuric acid / 0.5 mol / L aniline solution for at least 8 h, allowing aniline to be pumped into the gel via a concentration gradient. PANI polymerization is then carried out under ice bath conditions at 0-4°C. 20 mL of a prepared APS-sulfuric acid solution is slowly added dropwise, with a molar ratio of APS to aniline of 1:1 and a sulfuric acid concentration of 1 mol / L. The dropwise addition rate is approximately 3... When adding APS dropwise, rapid stirring is required at the beginning to ensure that the concentration of APS does not become too high in some areas. In the first 3 minutes, the solution will only show a light blue color. If a metallic luster appears on the surface of the solution within the first 3 minutes, it indicates that the polymerization is too fast, which may be due to burst polymerization. This indicates that the APS drop rate is too fast or the system temperature is too high or the temperature rises too quickly. It is necessary to adjust to a lower temperature or reduce the APS flow rate. The APS is completely added in about 15 minutes. At this time, stirring should be maintained for 1 hour, and then the stirring should be stopped to avoid the device being thinned due to prolonged stirring. The polymerization reaction will be completely polymerized after 8 hours. The temperature should be kept low throughout the process. After the polymerization is completed, the device is taken out, the excess PANI around the perimeter is cut off, and it is dried for two days under room temperature ventilation to obtain the PANI / GO-PVA-GLU / PANI dry-state dual-gel flexible all-solid-state supercapacitor device.

[0028] APS, its purity White solid granules, used as an oxidant to catalyze the in-situ polymerization of aniline monomers into PANI; the concentration of the aniline monomer solution is ≥99.5%, and the density is 1.022 g / cm³. 3 It is a yellow, transparent, oily liquid used for in-situ polymerization of PANI.

[0029] The preparation of GO suspension #1 includes: Graphene oxide (GO) was synthesized from flake graphite (2 g) using a modified Hummers method. In the conventional process, 1 g of NaNO3 was first completely dissolved in 70 ml of 98% H2SO4, stirred at room temperature until completely dissolved. The resulting solution was then cooled to 0–4 °C in an ice-water bath. Next, 2 g of flake graphite was added, and the mixture was stirred for 40 minutes. Then, 8 g of KMnO4 was slowly added; pouring too quickly at this point could lead to uneven mixing or even boiling. The reaction was continued at this low temperature for 30 minutes, during which the solution gradually turned dark green, indicating intercalation and initial oxidation. The mixture was then heated to 40 °C and stirred for 5 hours for further oxidation. At this point, the solution should turn brown. This solution was then slowly added to 240 mL of deionized water, maintaining the temperature between 65–75 °C, and stirred for 2 hours. The temperature was then increased to 95 °C, and after stirring for 5 minutes, 25 mL of 30% H2O2 was added. The product was then treated with 40 ml of 5% hydrochloric acid and stirred for 30 minutes. Finally, the obtained solid was collected by centrifugation, washed with deionized water until the supernatant reached a neutral pH, and diluted to 1000 ml to obtain a 2 mg / ml graphene oxide solution. This solution was then dispersed using ultrasound at 1500 W for 2 hours. Further, the GO nanosheets were exfoliated through 10 freeze-thaw cycles. By varying the amount of deionized water added in subsequent dilutions, the concentration of the graphene oxide suspension could be altered, creating concentration gradients of 2 mg / ml, 3 mg / ml, 4 mg / ml, and 5 mg / ml.

[0030] Example 1: A detailed description of the investigation into the changes in aniline and GO concentrations according to the present invention; This example illustrates the effects of aniline concentration and graphene oxide concentration on the performance of the obtained flexible solid-state supercapacitor; glucose was not added.

[0031] (1) Preparation of PVA / GO hydrogel: 1 g of polyvinyl alcohol (PVA) was added to 10 mL of graphene oxide (GO) suspension with a concentration of 2 mg / mL. The solution swelled at 60 °C, then the temperature was raised to 85 °C and stirred continuously until the solution was completely clear, yielding a GO-PVA sol. The sol was allowed to stand at 60 °C to eliminate air bubbles, then poured into a mold and subjected to repeated freeze-thaw cycles 2–3 times to obtain physically cross-linked block-shaped GO-PVA hydrogels. It should be noted that to obtain samples with better cycling stability, the number of freeze-thaw cycles should be appropriately reduced, but it is still necessary to ensure that the gel is completely cross-linked; otherwise, the gel is easily broken during subsequent polymerization. The resulting hydrogel was cut into 20 mm × 30 mm × 3 mm blocks and sealed for later use. By adjusting the concentration of the GO suspension (0, 2, 3, 4, 5 mg / mL), GO-PVA hydrogels with different GO contents can be prepared.

[0032] (2) Aniline polymerization and construction of flexible all-solid-state supercapacitors (FASC): Preparation of solution A: Mix 0.744 g of aniline (AN) with 20 mL of 1 mol / L H2SO4 aqueous solution, and immerse two small pieces of the gel electrolyte prepared above in the solution for 24 hours.

[0033] Preparation of solution B: Dissolve 1.824 g of ammonium persulfate (APS) in 20 mL of 1 mol / L H2SO4 aqueous solution.

[0034] Under magnetic stirring, solution B was slowly added to solution A, and stirring was continued at 0–4°C for 2 hours. Stirring was then stopped, and the mixture was allowed to stand for 8 hours to ensure complete polymerization. After the reaction, the gel block was removed, revealing a dark green polyaniline (PANI) polymerized on its surface, thus obtaining a FASC with PANI hydrogel polymerized on its surface. This FASC was dialyzed in a 1 mol / L H₂SO₄ solution until no color dissolution occurred. Finally, the four edges of the dialyzed FASC were trimmed neatly to prevent short circuits, and a carbon cloth of matching size was placed on its surface as a current collector, yielding the FASC for testing.

[0035] In the above process, the concentration of aniline was 0.4 mol / L, the concentration of GO was 2 mg / mL, and the molar ratio of APS to AN was maintained at 1:1.

[0036] (3) Optimization of aniline and GO concentrations: A series of samples with different PANI contents were prepared by varying the aniline concentration (0.4, 0.5, and 0.6 mol / L). Results analysis is shown below. Figure 8 .

[0037] A series of samples with different GO contents were prepared by varying GO concentrations (0, 2, 3, 4, 5 mg / mL). Results analysis is shown below. Figure 7 .

[0038] Unlike FASC without GO, GO-containing supercapacitors (G-SC) need to be dried in a ventilated environment for 48 hours after polymerization. Then, carbon cloth of similar size is attached to two opposite sides as current collectors for two-electrode testing.

[0039] Example 2: This embodiment illustrates the use of glucose (GLU) as a pore-forming agent in gels to construct porous structures and achieve internal polymerization, thereby improving device performance.

[0040] (1) Preparation of porous GO-PVA-GLU hydrogel: Glucose (GLU) of 0 g / 10 mL to 1.5 g / 10 mL was added as a pore-forming agent to PVA / GO sol (prepared using the same method as in Example 1), and the mixture was stirred until the solution became clear to obtain GO-PVA-GLU sol. This sol was subjected to repeated freeze-thaw cycles 3 to 4 times to obtain a solid GO / PVA / GLU hydrogel. Subsequently, the hydrogel was dialyzed with a large amount of deionized water to dissolve the GLU, thereby obtaining a porous GO-PVA-GLU hydrogel with more pores. Experiments showed that the flexibility of the gel significantly improved with increasing GLU addition, but the gel obtained at a GLU concentration of 1.5 g / 10 mL exhibited poor mechanical properties and was easily torn during polymerization due to stirring.

[0041] (2) Aniline polymerization and construction of bigel network in porous hydrogels The porous GO-PVA-GLU hydrogel prepared above was immersed in AN / H2SO4 solutions of different concentrations for 24 hours to allow sufficient AN to be absorbed into the pores. Since the porous structure theoretically requires more AN for polymerization, this example investigated the polymerization effect at AN concentrations of 0.4, 0.5, and 0.6 mol / L. Subsequent polymerization and treatment steps were the same as in Example 1. Unlike Example 1, due to the presence of the porous structure, the polymerization reaction occurred not only on the gel surface but also inside the gel, forming a PVA / PANI bigel network. As a control, a sample without GO and polymerized using only a 0.4 mol / L AN concentration was prepared.

[0042] (3) Optimization of glucose concentration: With a fixed AN concentration of 0.5 mol / L, the addition amounts of GLU were adjusted to 0 g / 10 mL, 0.5 g / 10 mL, 1 g / 10 mL, and 1.5 g / 10 mL to obtain the GLU concentration with the best overall performance. Electrical performance tests showed that the device exhibited the best performance when the GLU addition amount was 1 g / 10 mL.

[0043] The test results for Examples 1 and 2 are analyzed as follows: Test conditions: The electrochemical performance of the CNT / PANI paper-based aerogel composite electrode material was tested using an electrochemical workstation (DH7000C, Donghua Analytical). The device was tested using a two-electrode system with a diameter of 1 × 1 cm⁻¹. 2The PANI / GO-PVA-GLU / PANI dry-state dual-gel flexible all-solid-state supercapacitor was connected to the testing instrument via a carbon cloth current collector. The electrolyte was a 1 mol / L H2SO4 solution, but the electrolyte was completely removed after drying, and the sulfuric acid formed a stable ionic state (solid state) with PANI. The galvanostatic charge-discharge (GCD, electrochemical window 0–0.8 V) curves and cycle stability (GCD method, 2100 cycles, current density 1 mA / cm²) were tested. 2 (Electrochemical window: 0–0.8 V) and rate stability (current density: 0.2–1 mA / cm²). 2 The electrochemical window was 0–0.8 V. The tensile properties of the PANI / GO-PVA-GLU / PANI dry-state dual-gel flexible all-solid-state supercapacitor were tested using an Instron 3349 (Instron, USA) at a tensile speed of 50 mm / min. A 4 × 1 cm... 2 The specific capacitance retention rate of the CNT / PANI paper-based aerogel composite electrode was tested after 10,000 cycles of stretching and compression, and its mechanical stability was determined by repeated stretching and compression during charge and discharge.

[0044] Test Result Analysis: (1) Combination Figure 1 Figures a and b show the cross-sections of the PANI / GO-PVA / PANI dry-state double-gel flexible all-solid-state supercapacitor after compression drying, and Figures c and d show the cross-sections of the freeze-dried (uncompressed) device. It can be seen that the device has a sandwich structure, and the freeze-drying process results in larger pores while the pressurized drying process results in smaller pores.

[0045] (2) Combination Figure 2 The following are optical microscopic images of the present invention at different GLU concentrations: Figure a shows the device without GLU, and Figures b, c and d show the devices with 1 g / 10 ml GLU. Figures b to d show the morphology of the devices when the aniline concentration is 0.4, 0.5 and 0.6 mol / L. The device before the addition of GLU has a very obvious PVA / PANI interface. The addition of GLU plays a key role in the construction of the device's dual gel network.

[0046] (3) Combination Figure 3 The overall thickness of the device after drying is approximately 0.43–0.55 mm.

[0047] (4) Combination Figure 4 Figures a and b show the size and number of layers of GO; the graphene oxide has been successfully separated by ultrasonic dispersion, with only a small number of layers remaining.

[0048] (5) Combination Figure 5Figure 1 shows a macroscopic photograph of the PANI / GO-PVA / PANI dry-state dual-gel flexible all-solid-state supercapacitor prepared in this invention; Figure 2 shows the device bent and folded into different shapes; the device can be stretched, compressed, and folded, exhibiting good flexibility.

[0049] (6) Combination Figure 6 Figure 1 shows the mechanical performance test results of the present invention. Figure 2 shows the discharge of the PANI / GO-PVA / PANI dry-state dual-gel flexible all-solid-state supercapacitor under repeated stretching and compression. Figure 3 shows the tensile strength of the PANI / GO-PVA-GLU / PANI device with different GLU addition amounts. Figure 4 shows the comparison of the PANI / GO-PVA / PANI device after 10,000 stretching and compression cycles. During the GCD test, the device underwent repeated stretching and compression cycles (0.1–0.4 Hz, 40% strain) to simulate mechanical loads such as joint movement. The capacitance retention rate was 89% under slow deformation (0.05 Hz) and 83% under rapid deformation (0.4 Hz). In the tensile test, the device with a glucose concentration of 0 g / 10 ml achieved a high tensile strength of 2.4 MPa (154% strain), while the device with a glucose concentration of 0.5 g / 10 ml reached 3.1 MPa (358% maximum strain). The P420 at a glucose concentration of g / 10 ml reached 3.2 MPa (475% maximum strain).

[0050] (7) Combination Figure 7 Figure 1 shows the electrochemical performance of the device prepared by PANI / GO-PVA / PANI according to the present invention. Figure 2 shows the preparation of GO-PVA gel: Figure 3 shows the area specific capacitance calculated from the GCD curves of devices with different GO contents; Figure 4 shows the EIS diagram of devices with different GO contents; Figure 5 shows the GCD curves of the device prepared with a GO concentration of 2 mg / mL at different current densities. The area specific capacitance is optimal when the GO content is 2 mg / mL, and the EIS diagram also shows that the impedance decreases with the addition of GO, which proves that GO promotes ionic conductivity.

[0051] (8) Combination Figure 8 Figure a shows the electrochemical performance test results of the PANI / GO-PVA-GLU / PANI device of this invention, prepared by polymerization of aniline monomers at different concentrations and the addition of glucose at a concentration of 1 g / 10 mL: Figure a shows the device at 1 mA·cm -2 Figure b shows the GCD plot of the device at current density; Figure b shows the device at 10 mV·s. -1 The CV plot at the scan rate; the maximum areal capacitance is obtained with 0.5 M aniline at a glucose concentration of 1 g / 10 ml.

[0052] (9) Combination Figure 9 Figure a shows a comparison of the optimal electrochemical performance samples of the PANI / GO-PVA / PANI device and the PANI / GO-PVA-GLU / PANI device of the present invention; Figure a shows the device at 1 mA·cm -2 Figure b shows the GCD plot of the device at current density; Figure b shows the device at 10 mV·s. -1 The CV graphs at the scanning rate were compared. The sample with the best electrochemical performance without GLU and the sample with the best electrochemical performance after adding GLU to create pores were compared. It can be seen that the device with better electrochemical performance after adding GLU to create pores has better electrochemical performance because more polyaniline was polymerized and there is a PVA / PANI dual gel network.

[0053] (10) Combination Figure 10 Figure 1 shows the rate performance test results of the PANI / GO-PVA-GLU / PANI device of this invention; Figure 2 shows the rate performance test results at different current densities (1 mA·cm). -1 Figure 1 shows the GCD curve; Figure 2 shows the CV curves at different scan rates; Calculations based on the GCD curves show that the device with 1 g / 10 ml glucose and 0.5 M aniline operates at 1 mA / cm². 2 and 0.2 mA / cm 2 At the given current density, the area (volume) capacitance reached 835.0 mF / cm². 2 (17.8 F / cm) 3 ) and 877.0 mF / cm 2 (18.7 F / cm) 3 Meanwhile, the coulombic efficiency is 95.4%, and calculations using the GCD curve show that it can reach 800 μW / cm². 2 It has a power density of 74.2 μWh / cm³. 2 Energy density and at 160 μW / cm 2 It achieved a power density of 78.0 μWh / cm³. 2 Energy density.

[0054] (11) Combination Figure 11 Figure 1 shows the electrochemical performance changes of the PANI / GO-PVA-GLU / PANI device of the present invention after different drying times; Figure 2a shows the electrochemical performance changes at 1 mA·cm⁻¹ after different drying times. -1 Figure 1 shows the discharge curves of the device at the given current density; Figure 2b shows the discharge curves after drying for different times at 10 mV·s. -1The CV curves of the device at different scanning speeds are shown in Figure a. Figure a shows the discharge curves of the GCD. It can be seen that the sample dried for 48 h (initial drying) has the longest discharge time, and not the longest drying time of 528 h. The shortest discharge time is observed at 408 h, but even then, the performance is only less than 20% different, maintaining a relatively consistent shape with drying time. Each curve shows a relatively flat discharge plateau between 0.1 and 0.3 V, corresponding to a large reduction peak at 0.2 V in Figure b. In the CV curves of Figure b, only the sample dried for 48 h shows two clear oxidation peaks, and its reduction peak is also the clearest, indicating that the electrochemical reaction rate (mainly due to changes in ion transfer resistance) changes after prolonged drying.

[0055] (12) Combination Figure 12 The curves show the changes in areal capacitance of the PANI / GO-PVA-GLU / PANI device after different drying times. It can be seen that as drying progresses, the areal capacitance changes by less than 10% at the worst.

[0056] (13) Combination Figure 13 The figures show the curves of the areal capacitance and coulombic efficiency of the PANI / GO-PVA-GLU / PANI device of this invention after 2100 charge-discharge cycles; at 1 mA / cm² 2 The cycling stability of the PANI / GO-PVA-GLU / PANI device was tested at a current density of [value missing]. The curve showed an overall downward trend, but the capacity retention rate exceeded 100% in the first 1000 cycles. The capacity showed an increasing trend in the first 20 cycles, and then the overall capacity showed a decreasing trend. Finally, after 2100 charge-discharge cycles, 90.4% of the areal capacitance remained, demonstrating good cycling stability.

[0057] (14) Combination Figure 14 Figure 1 shows the performance changes of the PANI / GO-PVA-GLU / PANI device of this invention at extreme low temperatures; Figure a shows the changes in GCD curves at 25℃, 0℃, -10℃, -20℃, and -30℃; Figure b shows the changes in CV curves at 25℃, 0℃, -10℃, -20℃, and -30℃; Figure c shows the changes in EIS curves at 25℃, 0℃, -10℃, -20℃, and -30℃; Figure d shows the activation energy calculated by linear fitting of ionic conductivity; the liquid-free device also exhibits excellent freeze resistance. To test the performance of SCs in low-temperature environments, we tested the electrochemical performance of the device in the temperature range of 25℃ to -30℃. Figure a shows the GCD curves at different temperatures, 1 mA / cm². 2At current densities ranging from room temperature to -30°C, the device maintained 56.9% of its areal capacitance; the voltage drop increased from approximately 0.18 V to 2.6 V; the device maintained a capacitance of 675 mF / cm² at 0°C, -10°C, and -20°C. 2 (88.8%), 625 mF / cm 2 (82.2%), 567.5 mF / cm 2 (74.7%) This is a fairly high level. As the temperature decreases, the CV curve of the device in Figure b gradually approaches a spindle shape, and the oxidation peak and reduction peak move towards their respective voltage peaks, indicating that the proportion of non-Radidatic processes (double-layer charging and discharging) on ​​the electrodes increases relatively with the change of temperature; Figures c and d are obtained by plotting the logarithm of the ionic conductivity at each temperature against the reciprocal of the absolute temperature, and then performing linear fitting on all the points obtained to calculate the activation energy of the device, Ea = 0.145 eV, which meets the requirements for the existence of the proton hopping mechanism. Furthermore, after removing the points at room temperature, the activation energy of the device is only Ea = 0.242 eV, which also meets the requirements for the existence of the proton hopping mechanism.

[0058] (15) Combination Figure 15 The CV curves of the PANI / GO-PVA / PANI dry-state dual-gel flexible all-solid-state supercapacitor after drying for 6 months were tested at different scan speeds. It can be seen that the shape of the curve has not changed much from the shape at room temperature. Compared with the area ratio capacitance in the initial state, it is calculated that 92.6% of the capacitance is retained.

[0059] (16) Combination Figure 16 PANI / GO-PVA / PANI devices without added glucose were tested at different temperatures. The devices also exhibited good low-temperature performance; the CV curve remained almost unchanged as the temperature decreased, although the impedance increased slightly with decreasing temperature. The activation energy of the device was calculated to be Ea = 0.175 eV. Furthermore, the tensile curves at room temperature and low temperature were very similar, all of which demonstrate that the PANI / GO-PVA / PANI devices possess excellent low-temperature performance. (17) Combining Figure 17 The electrochemical performance of the PANI / GO-PVA / PANI device was tested after it was dried in air. The device performance was not positively correlated with the relative humidity of the air, proving that the device is not dependent on humidity. This reflects the device's drought resistance and the Grotthuss mechanism.

[0060] (18) Combination Figure 18Thermogravimetric analysis was performed on the PANI / GO-PVA / PANI device after it had been dried for 10 days. It can be seen that there were almost no mass change peaks before 120℃, which proves that the device is in the anhydrous stage after being dried at room temperature for more than 10 days, but the device can still maintain its function for more than half a year.

[0061] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0062] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0063] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A fully dry supercapacitor based on GO-PVA dry gel electrolyte, characterized in that, The capacitor is a device with a PANI / GO-PVA / PANI sandwich structure and a thickness of 0.43–0.55 mm. GO-PVA is a gel electrolyte, and PANI is an electrode with a network-like porous structure formed by in-situ polymerization on both sides of the electrolyte. Efficient proton channels are formed in the GO-PVA electrolyte and at the interface between it and the PANI electrode through a network of interconnected hydrogen bonds.

2. The method for preparing a fully dry supercapacitor based on GO-PVA dry gel electrolyte according to claim 1, characterized in that, Using GO and PVA as raw materials, a pre-formed GO-PVA gel electrolyte was prepared by freeze-thaw mixing. After being immersed in an aniline solution, polyaniline electrodes were directly grown on both sides of the pre-formed GO-PVA gel electrolyte through in-situ polymerization. After pressing and drying, a PANI / GO-PVA / PANI device with a continuous hydrogen bond network proton hopping transport channel was obtained. The amount of GO added was 0–5 mg / mL, the concentration of aniline solution was 0.2–0.5 mol / L, and the amount of PVA added was 10 wt%.

3. The method for preparing a fully dry supercapacitor based on GO-PVA dry gel electrolyte according to claim 2, characterized in that, The GO mentioned is GO nanosheets, with a size of 100 nm to 3 μm. The edges of the GO nanosheets are irregular, and there are obvious wrinkles on the surface of the sheets.

4. The method for preparing a fully dry supercapacitor based on GO-PVA dry gel electrolyte according to claim 2, characterized in that, The polymerization temperature of the in-situ polymerization is not higher than 4°C, and after rapid stirring for the first hour, it is allowed to stand for 8 hours to completely polymerize. The pressing and drying process involves drying for 48 hours under ambient ventilation conditions.

5. A fully dry supercapacitor based on GO-PVA dry gel electrolyte, characterized in that, Based on the PANI / GO-PVA / PANI sandwich structure of the fully dry supercapacitor based on GO-PVA dry gel electrolyte as described in any of claims 1-3, GLU is introduced to create pores, resulting in a GLU-modified PANI / GO-PVA / PANI sandwich structure dry gel flexible all-solid-state supercapacitor.

6. The method for preparing a fully dry supercapacitor based on GO-PVA dry gel electrolyte according to claim 5, characterized in that, GO-PVA-GLU gel was prepared, and PANI electrode was formed by in-situ polymerization on the gel surface; The preparation process includes: dispersing GO in water at a mass ratio of 0-5 mg / mL to prepare a suspension, adding 0-2 g of glucose, heating and stirring to form a GO-PVA-GLU sol with PVA, repeatedly freezing and thawing 3-4 times to obtain an electrolyte, dialyzing out GLU in water, then soaking in an aniline solution overnight, and adding APS to initiate polymerization.

7. The method for preparing a fully dry supercapacitor based on GO-PVA dry gel electrolyte according to claim 2 or 6, characterized in that, The freeze-thaw cycle is described as freezing at -25°C for 1 hour and thawing for 15 minutes, followed by repeated freeze-thaw cycles.

8. The method for preparing a fully dry supercapacitor based on GO-PVA dry gel electrolyte according to claim 6, characterized in that, The GO-PVA-GLU electrolyte gel was soaked in an aniline solution for more than 8 hours; then, the oxidant APS solution was added dropwise at a temperature of 0-4 °C every 3 seconds to initiate polymerization, while the system required rapid stirring.

9. The method for preparing a fully dry supercapacitor based on GO-PVA dry gel electrolyte according to claim 6, characterized in that, The preparation of the aniline solution includes: 1.1 ml of sulfuric acid, 0.744 g of aniline monomer, and 18.9 ml of water, to prepare a pale yellow and clear solution; The preparation of the APS solution includes: 1.1 ml of sulfuric acid, 18.9 ml of water, and APS prepared into a clear solution; The aniline monomer solution has a concentration ≥99.5% and a density of 1.022 g / cm³. 3 The sulfuric acid concentration is 98% and the density is 1.84 g / cm³.

10. The application of the fully dry supercapacitor based on GO-PVA dry gel electrolyte as described in claim 1 or 5 in the preparation of wearable flexible electronic materials.

Images