Multicolor electrochromic gel material, preparation method and application thereof, electrochromic gel device and preparation method thereof

Abstract

The invention belongs to the technical field of photoelectric materials, and provides a multicolor electrochromic gel material, a preparation method and application thereof, an electrochromic gel device and a preparation method thereof. The multicolor electrochromic gel material comprises polyaniline powder, a P2W18 solution and an Arabic gum solution, the volume ratio of the P2W18 solution to the Arabic gum solution is (1: 1)-(10: 1). The invention further provides a preparation method and application of the multicolor electrochromic gel material. The invention also provides an electrochromic device and a preparation method thereof. On the basis of the synergistic effect of polyaniline and P2W18, P2W18 and polyaniline form electrode complementation in the device, the physical cross-linking characteristic of Arabic gum is utilized, a three-dimensional network structure is formed through low-temperature crystallization-room-temperature melting circulation, polyaniline and P2W18 are stably fixed, and the device can achieve four-stage color change of transparency, blue color, green color and yellow color.

Description

Technical Field

[0001] The present invention belongs to the technical field of optoelectronic materials, and in particular relates to a multi-color-changing electrochromic gel material and a preparation method and application thereof, as well as an electrochromic gel device and a preparation method thereof. Background Art

[0002] Improving the performance of electrochromic devices relies on innovations in material preparation processes and optimization of device structures. Traditional electrochromic materials have a single color, making it difficult to achieve multicolor changes. Existing technologies have improved the device's multicolor rendering capability and response speed through material composites, such as TiO2 and viologens composite ion gels. However, viologens require complex organic synthesis processes and expensive raw materials, resulting in high device manufacturing costs. Furthermore, the complex preparation process for these gels can easily lead to localized gelation failure or optical inhomogeneity.

[0003] Furthermore, existing gel-based electrochromic materials suffer from long gelling times, poor uniformity, slow color change response, and a narrow light modulation range. Furthermore, the single electrode material limits the device's application in flexible and wearable applications. Therefore, there is an urgent need to develop a multi-color electrochromic gel material, its preparation method, its application, and an electrochromic gel device and its preparation method. Summary of the Invention

[0004] In order to solve the above-mentioned technical problems, the present invention provides a multi-color-changing electrochromic gel material and a preparation method and application thereof, as well as an electrochromic gel device and a preparation method thereof.

[0005] The technical solution adopted by the present invention is: a multi-color electrochromic gel material, including polyaniline powder, P2W 18 Solution and gum arabic solution; the P2W 18 The volume ratio of the solution to the gum arabic solution is 1:1-10:1; The gum arabic solution is specifically prepared by dissolving 2g-5g of gum arabic in 100ml of deionized water to prepare a 2-5wt% gum arabic solution; P2W 18 The specific solution is: 1g-3g of P2W 18 Dissolve in 50 mL of N,N-dimethylformamide to prepare P2W 18 solution, the P2W 18 It is a Dawson type polyoxometalate K6[α-P2W 18 O 62 ]·14H2O; The added amount of polyaniline powder accounts for 10%-20% of the mass of gum arabic.

[0006] Furthermore, the polyaniline powder is prepared by polymerizing aniline and ammonium persulfate in a reactor, and the synthesis method is specifically as follows: First, aniline was dissolved in 1 mol / L hydrochloric acid solution to prepare an aniline solution with a concentration of 0.5 mol / L-1 mol / L; Then, sodium persulfate was added to the aniline solution as an oxidant, stirred evenly, and then transferred to a reactor. The molar ratio of sodium persulfate to aniline was 1:1. Finally, the reactor was sealed and the temperature of the reactor was set to 120° C. to carry out polyaniline synthesis reaction for 6 h. After the reaction was completed, the reaction was cooled to room temperature, washed repeatedly with deionized water and ethanol, and vacuum dried to obtain polyaniline powder.

[0007] The present invention also provides a method for preparing the multi-color electrochromic gel material, which specifically comprises the following steps: (1) Take polyaniline powder and P2W according to the above ratio 18 solution and gum arabic solution; (2) Preparation of Gum Arabic-P2W 18 Mixed solution: According to the above volume ratio, the gum arabic solution and P2W 18 The solutions were mixed and ultrasonically dispersed for 30 min to obtain a uniform mixture, namely gum arabic-P2W. 18 Mixing solution; (3) Add polyaniline powder to the gum arabic-P2W prepared in step (2) 18 The mixed solution was magnetically stirred for 2 h until completely dispersed, poured into a mold, frozen at -20 °C for 12 h, and then thawed at room temperature for 8 h. The freeze-thaw cycle was repeated 2-3 times to obtain a multi-color electrochromic gel.

[0008] The present invention also provides an electrochromic device, comprising two pieces of FTO conductive glass, wherein the conductive surface of one piece of FTO conductive glass is covered with a conductive copper film, serving as a first electrode, and the other piece of FTO conductive glass is blank conductive glass, serving as a second electrode. The above-mentioned multi-color electrochromic gel is placed between the two pieces of FTO conductive glass, covering the conductive copper film.

[0009] Furthermore, the thickness of the conductive copper film is 50 nm-200 nm, and the thickness of the multi-color electrochromic gel is 50 μm-500 μm.

[0010] The present invention further provides a method for preparing the electrochromic device, which specifically comprises the following steps: (1) Deposition of conductive copper film on the surface of conductive glass by electropolymerization process: The FTO conductive glass was used as a substrate and immersed in a 1 mol / L sulfuric acid solution containing 0.3 mol / L copper sulfate. A platinum sheet was used as a counter electrode and electropolymerization was carried out at a constant potential of -0.3V-0.5V for 30 minutes to deposit a conductive copper film on the surface of the FTO conductive glass. The glass was then rinsed with deionized water and ethanol and dried for later use. (2) Prepare 1 mol / L propylene carbonate solution containing lithium ions: Dissolve 1.06 g of lithium perchlorate in 10 ml of propylene carbonate solution and stir at 70°C for 30 minutes to obtain a uniform 1 mol / L propylene carbonate solution containing lithium ions, i.e., the electrolyte solution; (3) Cut the multi-color electrochromic gel into sheets that match the size of the FTO conductive glass, soak them in the electrolyte solution prepared in step (2), and soak them for 1 hour; take them out and place them on a blank conductive glass, and then cover them on another piece of FTO conductive copper film. The two pieces of FTO conductive glass clamp the multi-color electrochromic gel, and the edges are sealed with silicone rubber to obtain an electrochromic gel device.

[0011] Compared with the prior art, the present invention has the following beneficial effects: The multi-color electrochromic gel material of the present invention is based on polyaniline and P2W 18 The synergy of P2W 18 In the device, it forms an electrode complementary with polyaniline, and utilizes the physical cross-linking properties of gum arabic to form a three-dimensional network structure through low-temperature crystallization-room-temperature melting cycles. 18 A stable fixation is formed, so that the electrochromic device can achieve four-level color changes of transparent (2V) - blue (-2.0V) - green (-0.5V) - yellow (0V) in the voltage range of -2.0V to 2V. When the potential increases, the oxidation of polyaniline is promoted, and the ratio of benzo / quinone units in the molecular structure of polyaniline and the protonation state are jointly regulated, expanding the conjugated system, resulting in a red shift in the absorption spectrum, and the color changes from yellow to green and blue, showing a blue-green-yellow three-color change; when the potential is reduced, the reduction process drives the reverse color change, and the light modulation can reach more than 69%.

[0012] The multi-color electrochromic gel material of the present invention adopts freeze-thaw gelation technology, abandoning traditional electrochemical polymerization or chemical cross-linking agents, and utilizing the physical cross-linking properties of gum arabic to form a three-dimensional network structure through a low-temperature crystallization-room temperature melting cycle. The gelation time is shortened to 1 / 3 of that of the traditional method, and the gel uniformity is improved. Polyaniline polymerization adopts a reactor synthesis process, and the controllable polymerization of polyaniline is achieved in a high-temperature and high-pressure reactor environment. Compared with the traditional solution polymerization method, the product has a narrow molecular weight distribution and high crystallinity, which significantly improves the stability of the electrochromic performance. The electrochromic device uses an electropolymerization process to in-situ deposit a copper film on the surface of the conductive glass, breaking through the limitations of the traditional FTO electrode and expanding the application of electrochromic gel materials and electrochromic devices in flexible electronics, smart windows and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic structural diagram of the electrochromic device of the present invention.

[0014] Figure 2 This is a full spectrum diagram of the electrochromic device prepared in Example 1 under ultraviolet and visible light of 400nm-800nm ​​and an applied voltage of -2V-2V.

[0015] Figure 3 This is a full spectrum diagram of the electrochromic device prepared in Example 2 under ultraviolet and visible light of 400nm-800nm ​​and an applied voltage of -2V-2V.

[0016] Figure 4 This is a full spectrum diagram of the electrochromic device prepared in Example 3 under ultraviolet and visible light of 400nm-800nm ​​and an applied voltage of -2V-2V.

[0017] Figure 5 This is a full spectrum diagram of the electrochromic device prepared in Comparative Example 1 under ultraviolet and visible light of 400nm-800nm ​​and an applied voltage of -2V-2V.

[0018] Figure 6 This is a full spectrum diagram of the electrochromic device prepared in Comparative Example 2 under ultraviolet and visible light of 400nm-800nm ​​and applied voltage of -1.6V-1.6V.

[0019] In the picture, 1. FTO conductive glass, 2. Conductive copper film; 3. Multi-color electrochromic gel. DETAILED DESCRIPTION

[0020] In order to highlight the technical advantages and excellent performance of the present invention, the following will be further described with reference to the accompanying drawings and specific embodiments. The following specific embodiments are only used for the present invention, and the specific implementation process can also be adjusted according to the understanding of technicians and actual conditions.

[0021] Example 1

[0022] Multi-color electrochromic gel materials, including polyaniline powder, P2W 18 Solution and gum arabic solution; the P2W 18 The volume ratio of solution and gum arabic solution was 1:1; The gum arabic solution was prepared by dissolving 2 g of gum arabic in 100 ml of deionized water to prepare a 2 wt % gum arabic solution.

[0023] P2W 18 The specific solution is: 1g of P2W 18 Dissolve in 50 mL of N,N-dimethylformamide to prepare P2W 18 solution, the P2W 18 It is a Dawson type polyoxometalate K6[α-P2W 18 O 62 ]·14H2O; Dawson type polyoxometalate K6[α-P2W 18 O 62 ]·The synthesis method of 14H2O is as follows: First, 30 g of Na2WO4·2H2O was added to 30 mL of deionized water and completely dissolved to obtain a colorless solution. Then, 15 mL of HCl solution and 15 mL of H3PO4 solution were added in sequence to obtain a light yellow clear solution. The mixture was then refluxed at 130°C for 24 h. After reflux, 30 g of KCl was added to obtain a yellow precipitate, which was filtered and air-dried for 2 h to obtain a crude product. Finally, the crude product was dissolved in water and filtered to remove the insoluble matter. The filtrate was heated and evaporated to 20 mL-30 mL, cooled to room temperature, and allowed to stand for 3 days to obtain a crystalline product, which is the Dawson type polyacid K6[α-P2W 18 O 62 ]·14H2O.

[0024] The amount of polyaniline powder added is 10% of the mass of gum arabic. (In this example, the amount added is 0.2g) The polyaniline powder is prepared by polymerizing aniline and ammonium persulfate in a reactor. The specific synthesis method is as follows: First, 5g-10g of aniline was dissolved in 100mL of 1mol / L hydrochloric acid solution to prepare an aniline solution with a concentration of 0.5mol / L-1mol / L; Then, sodium persulfate was added to the aniline solution as an oxidant, stirred evenly, and then transferred to a reactor. The molar ratio of sodium persulfate to aniline was 1:1. Finally, the reactor was sealed and the temperature of the reactor was set to 120° C. to carry out polyaniline synthesis reaction for 6 h. After the reaction was completed, the reaction was cooled to room temperature, washed repeatedly with deionized water and ethanol, and vacuum dried to obtain polyaniline powder.

[0025] The use of the multi-color electrochromic gel material of Example 1 in preparing a multi-color electrochromic gel 3, and the method for preparing the multi-color electrochromic gel 3 specifically include the following steps: (1) Take polyaniline powder and P2W according to the above ratio 18 solution and gum arabic solution; (2) Preparation of Gum Arabic-P2W 18 Mixed solution: According to the above volume ratio, the gum arabic solution and P2W 18 The solutions were mixed and ultrasonically dispersed for 30 min to obtain a uniform mixture, namely gum arabic-P2W. 18 Mixing solution; (3) Add polyaniline powder to the gum arabic-P2W prepared in step (2) 18 The mixed solution was magnetically stirred for 2 h until completely dispersed, poured into a mold, frozen at -20 °C for 12 h, and then thawed at room temperature for 8 h. The freeze-thaw cycle was repeated 2-3 times to obtain a multi-color electrochromic gel 3.

[0026] The electrochromic device includes the multi-color-changing electrochromic gel 3 prepared by the method for preparing the multi-color-changing electrochromic gel 3.

[0027] like Figure 1 As shown, the electrochromic device includes two pieces of FTO conductive glass 1, the conductive surface of one piece of FTO conductive glass 1 is covered with a conductive copper film 2, which serves as a first electrode, and the other piece of FTO conductive glass 1 is blank conductive glass, which serves as a second electrode. A multi-color electrochromic gel 3 is placed between the two pieces of FTO conductive glass 1 to cover the conductive copper film 2.

[0028] The thickness of the conductive copper film 2 is 50 nm to 200 nm, and the thickness of the multi-color electrochromic gel 3 is 50 μm to 500 μm.

[0029] The method for preparing the electrochromic device specifically comprises the following steps: (1) Depositing a conductive copper film on the surface of conductive glass by electropolymerization process 2: Use FTO conductive glass 1 as a substrate and immerse it in a 1 mol / L sulfuric acid solution containing 0.3 mol / L copper sulfate. Use a platinum sheet as a counter electrode and electropolymerize at a constant potential of -0.3V-0.5V for 30 minutes to deposit a conductive copper film 2 on the surface of the FTO conductive glass 1. Rinse with deionized water and ethanol and dry for later use. (2) Prepare 1 mol / L propylene carbonate solution containing lithium ions: Dissolve 1.06 g of lithium perchlorate in 10 mL of propylene carbonate solution and stir at 70°C for 30 minutes to obtain a uniform 1 mol / L propylene carbonate solution containing lithium ions, i.e., the electrolyte solution; (3) Cut the multi-color electrochromic gel 3 into sheets that match the size of the FTO conductive glass 1, soak them in the electrolyte solution prepared in step (2), and soak them for 1 hour; take them out and place them on a blank conductive glass, and then cover them on another piece of FTO conductive copper film 2. The two pieces of FTO conductive glass 1 clamp the multi-color electrochromic gel 3, and the edges are sealed with silicone rubber to obtain an electrochromic gel device.

[0030] Performance test: In the electrochromic device prepared in Example 1, the first electrode was used as the positive electrode and the second electrode was used as the negative electrode. The applied voltage was -2V-2V. The test was performed in a UV-visible spectrophotometer with a wavelength of 400nm-800nm. The transmittance of the electrochromic device changed as shown in the following figure: Figure 2 As shown, the light modulation of the device is 69.1%. Example

[0031] The difference from Example 1 is that: Multi-color electrochromic gel materials, including polyaniline powder, P2W 18 Solution and gum arabic solution; the P2W 18 The volume ratio of solution and gum arabic solution was 10:1; The gum arabic solution was prepared by dissolving 5 g of gum arabic in 100 ml of deionized water to prepare a 5 wt % gum arabic solution.

[0032] P2W 18 The specific solution is: 3g of P2W 18 Dissolve in 50 mL of N,N-dimethylformamide to prepare P2W 18 solution, the P2W 18 It is a Dawson type polyoxometalate K6[α-P2W 18 O 62 ]·14H2O.

[0033] The amount of polyaniline powder added is 20% of the mass of gum arabic. (In this example, the amount added is 1g) The polyaniline powder is prepared by polymerizing aniline and ammonium persulfate in a reactor. The specific synthesis method is as follows: First, 5g-10g of aniline was dissolved in 100mL of 1mol / L hydrochloric acid solution to prepare an aniline solution with a concentration of 0.5mol / L-1mol / L; Then, sodium persulfate was added to the aniline solution as an oxidant, stirred evenly, and then transferred to a reactor. The molar ratio of sodium persulfate to aniline was 1:1. Finally, the reactor was sealed and the temperature of the reactor was set to 120° C. to carry out polyaniline synthesis reaction for 6 h. After the reaction was completed, the reaction was cooled to room temperature, washed repeatedly with deionized water and ethanol, and vacuum dried to obtain polyaniline powder.

[0034] Performance test: In the electrochromic device prepared in Example 1, the first electrode was used as the positive electrode and the second electrode was used as the negative electrode. The applied voltage was -2V-2V. The test was performed in a UV-visible spectrophotometer with a wavelength of 400nm-800nm. The transmittance of the electrochromic device changed as shown in the following figure: Figure 2 As shown, the light modulation of the device is 69.1%.

[0035] Example 2

[0036] The difference from Example 1 is that: Multi-color electrochromic gel materials, including polyaniline powder, P2W 18 Solution and gum arabic solution; the P2W 18 The volume ratio of solution and gum arabic solution was 10:1; The gum arabic solution was prepared by dissolving 5 g of gum arabic in 100 ml of deionized water to prepare a 5 wt % gum arabic solution.

[0037] P2W 18 The specific solution is: 3g of P2W 18 Dissolve in 50 mL of N,N-dimethylformamide to prepare P2W 18 solution, the P2W 18 It is a Dawson type polyoxometalate K6[α-P2W 18 O 62 ]·14H2O.

[0038] The amount of polyaniline powder added is 20% of the mass of gum arabic. (In this example, the amount added is 1g) The polyaniline powder is prepared by polymerizing aniline and ammonium persulfate in a reactor. The specific synthesis method is as follows: First, 5g-10g of aniline was dissolved in 100mL of 1mol / L hydrochloric acid solution to prepare an aniline solution with a concentration of 0.5mol / L-1mol / L; Then, sodium persulfate was added to the aniline solution as an oxidant, stirred evenly, and then transferred to a reactor. The molar ratio of sodium persulfate to aniline was 1:1. Finally, the reactor was sealed and the temperature of the reactor was set to 120° C. to carry out polyaniline synthesis reaction for 6 h. After the reaction was completed, the reaction was cooled to room temperature, washed repeatedly with deionized water and ethanol, and vacuum dried to obtain polyaniline powder.

[0039] Performance test: In the electrochromic device prepared in Example 2, the first electrode was used as the positive electrode and the second electrode was used as the negative electrode. The applied voltage was -2V-2V. The test was performed in an ultraviolet-visible spectrophotometer with a wavelength of 400nm-800nm. The transmittance of the electrochromic device prepared in Example 2 changed as shown in FIG. Figure 3 As shown, the light modulation of the device is 69.3%.

[0040] Example 3

[0041] The difference from Example 1 is that: Multi-color electrochromic gel materials, including polyaniline powder, P2W 18 Solution and gum arabic solution; the P2W 18 The volume ratio of solution and gum arabic solution was 5:1; The gum arabic solution was prepared by dissolving 4 g of gum arabic in 100 ml of deionized water to prepare a 4 wt % gum arabic solution.

[0042] P2W 18 The specific solution is: 2g of P2W 18 Dissolve in 50 mL of N,N-dimethylformamide to prepare P2W 18 solution, the P2W 18 It is a Dawson type polyoxometalate K6[α-P2W 18 O 62 ]·14H2O.

[0043] The amount of polyaniline powder added is 15% of the mass of gum arabic. (In this example, the amount added is 0.6g) The polyaniline powder is prepared by polymerizing aniline and ammonium persulfate in a reactor. The specific synthesis method is as follows: First, 5g-10g of aniline was dissolved in 100mL of 1mol / L hydrochloric acid solution to prepare an aniline solution with a concentration of 0.5mol / L-1mol / L; Sodium persulfate was added to the aniline solution as an oxidant, and the mixture was stirred and then transferred to a reactor. The molar ratio of sodium persulfate to aniline was 1:1. The reactor was sealed and the temperature of the reactor was set to 120° C. to carry out polyaniline synthesis reaction for 6 hours. After the reaction was completed, the reaction was cooled to room temperature, washed repeatedly with deionized water and ethanol, and vacuum dried to obtain polyaniline powder.

[0044] Performance test: In the electrochromic device prepared in Example 3, the first electrode was used as the positive electrode and the second electrode was used as the negative electrode. The applied voltage was -2V-2V. The test was performed in an ultraviolet-visible spectrophotometer with a wavelength of 400nm-800nm. The transmittance of the electrochromic device prepared in Example 3 changed as shown in FIG. Figure 4 As shown, the light modulation of the device is 69.4%.

[0045] Comparative Example 1 The difference from Example 1 is that P2W is not added to the multi-color electrochromic gel material. 18 solution.

[0046] The rest are the same as in Example 1.

[0047] Performance test: In the electrochromic device prepared in comparative example 1, the first electrode is the positive electrode and the second electrode is the negative electrode. The applied voltage is -2V-2V. The wavelength is 400nm-800nm ​​in the ultraviolet-visible spectrophotometer. The transmittance change of the electrochromic device prepared in comparative example 1 is as follows: Figure 5 As shown, the light modulation of the device is 25.2%.

[0048] Comparative Example 2 The difference from Example 1 is that no polyaniline powder is added to the multi-color electrochromic gel material.

[0049] The rest are the same as in Example 1.

[0050] Performance test: In the electrochromic device prepared in comparative example 2, the first electrode is the positive electrode and the second electrode is the negative electrode. The applied voltage is -1.6V-1.6V. The wavelength is 400nm-800nm ​​in the ultraviolet-visible spectrophotometer. The transmittance change of the electrochromic device prepared in comparative example 2 is as follows: Figure 6 As shown, the light modulation of the device is 56.6%.

[0051] Through the performance tests of the above-mentioned Examples 1, 2, 3 and Comparative Examples 1 and 2, it can be seen that the light modulation range of Examples 1, 2 and 3 is higher than that of Comparative Examples 1 and 2. 18 With the synergistic effect of the nanostructured carbon fiber and gum arabic, the device can achieve four-level color changes from transparent (2V) to blue (-2.0V) to green (-0.5V) to yellow (0V) within the voltage range of -2.0V to 2V, and the light modulation can reach more than 69%.

[0052] It can be further seen from the optical modulation data of Examples 1, 2 and 3 that when P2W 18When the amount of polyaniline powder added is small, the device is more transparent when fading and lighter in color when colored, indicating that the amount of active material directly affects the light modulation range of the device.

[0053] The above content is only a preferred embodiment of the present invention. For ordinary technicians in this field, according to the concept of the present invention, many changes can be made in the specific implementation method and application scope. As long as these changes do not deviate from the concept of the present invention, they all fall within the scope of protection of the present invention.

Claims

1. Multi-color electrochromic gel material, characterized by: Including polyaniline powder, P2W 18 Solution and gum arabic solution; the P2W 18 The volume ratio of the solution to the gum arabic solution is 1:1-10:1; The gum arabic solution is specifically prepared by dissolving 2g-5g of gum arabic in 100ml of deionized water to prepare a 2-5wt% gum arabic solution; P2W 18 The specific solution is: 1g-3g of P2W 18 Dissolve in 50 mL of N,N-dimethylformamide to prepare P2W 18 solution, the P2W 18 It is a Dawson type polyoxometalate K6[α-P2W 18 O 62 ]·14H2O; The added amount of polyaniline powder accounts for 10%-20% of the mass of gum arabic.

2. The multi-color electrochromic gel material according to claim 1, characterized in that: The polyaniline powder is prepared by polymerizing aniline and ammonium persulfate in a reactor. The specific synthesis method is as follows: First, aniline was dissolved in 1 mol / L hydrochloric acid solution to prepare an aniline solution with a concentration of 0.5 mol / L-1 mol / L; Then, sodium persulfate was added to the aniline solution as an oxidant, stirred evenly, and then transferred to a reactor. The molar ratio of sodium persulfate to aniline was 1:

1. Finally, the reactor was sealed and the temperature of the reactor was set to 120° C. to carry out polyaniline synthesis reaction for 6 h. After the reaction was completed, the reaction was cooled to room temperature, washed repeatedly with deionized water and ethanol, and vacuum dried to obtain polyaniline powder.

3. The method for preparing the multi-color electrochromic gel material according to claim 1 or 2, comprising the following steps: (1) Take polyaniline powder and P2W according to the above ratio 18 solution and gum arabic solution; (2) Preparation of Gum Arabic-P2W 18 Mixed solution: According to the above volume ratio, the gum arabic solution and P2W 18 The solutions were mixed and ultrasonically dispersed for 30 min to obtain a uniform mixture, namely gum arabic-P2W. 18 Mixing solution; (3) Add polyaniline powder to the gum arabic-P2W prepared in step (2) 18 The mixed solution was magnetically stirred for 2 h until completely dispersed, poured into a mold, frozen at -20 °C for 12 h, and then thawed at room temperature for 8 h. The freeze-thaw cycle was repeated 2-3 times to obtain a multi-color electrochromic gel.

4. Use of the multi-color electrochromic gel material according to claim 1 or 2 in the preparation of a multi-color electrochromic gel.

5. An electrochromic device, characterized in that The invention comprises a multi-color-changing electrochromic gel prepared by the method for preparing a multi-color-changing electrochromic gel as claimed in claim 3.

6. The electrochromic device according to claim 5, wherein: It includes two pieces of FTO conductive glass, the conductive surface of one piece of FTO conductive glass is covered with a conductive copper film, which serves as the first electrode, and the other piece of FTO conductive glass is blank conductive glass, which serves as the second electrode. The above-mentioned multi-color electrochromic gel is placed between the two pieces of FTO conductive glass to cover the conductive copper film.

7. The electrochromic device according to claim 6, wherein: The thickness of the conductive copper film is 50nm-200nm, and the thickness of the multi-color electrochromic gel is 50μm-500μm.

8. The method for preparing an electrochromic device according to claim 6 or 7, wherein: The preparation method specifically comprises the following steps: (1) Deposition of conductive copper film on the surface of conductive glass by electropolymerization process: The FTO conductive glass was used as a substrate and immersed in a 1 mol / L sulfuric acid solution containing 0.3 mol / L copper sulfate. A platinum sheet was used as a counter electrode and electropolymerization was carried out at a constant potential of -0.3V-0.5V for 30 minutes to deposit a conductive copper film on the surface of the FTO conductive glass. The glass was then rinsed with deionized water and ethanol and dried for later use. (2) Prepare 1 mol / L propylene carbonate solution containing lithium ions: Dissolve 1.06 g of lithium perchlorate in 10 ml of propylene carbonate solution and stir at 70°C for 30 minutes to obtain a uniform 1 mol / L propylene carbonate solution containing lithium ions, i.e., the electrolyte solution; (3) Cut the multi-color electrochromic gel into sheets that match the size of the FTO conductive glass, soak them in the electrolyte solution prepared in step (2), and soak them for 1 hour; take them out and place them on a blank conductive glass, and then cover them on another piece of FTO conductive copper film. The two pieces of FTO conductive glass clamp the multi-color electrochromic gel, and the edges are sealed with silicone rubber to obtain an electrochromic gel device.

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