Universal electrochromic complementary counter electrode, preparation method and application method

Abstract

The invention discloses a universal electrochromic complementary counter electrode, a preparation method and an application method. The counter electrode comprises an electrochemical active substance A, conductive glass B, a binder C and a conductive agent D. The electrochemical active substance A has multiple redox couple at the same time, and the conductive glass B is used for bearing active substances in the electrochemical active substance A; the counter electrode is used for being matched with different electrochromic anodes / cathodes so as to form a complete electrochromic electrochemical system. The counter electrode disclosed by the invention can be used as an anode so as to form a complementary electrochromic device with a cathode electrochromic electrode, and can also be used as a cathode so as to form a complementary electrochromic device with an anode electrochromic electrode, so that the universal use of the cathode and the anode is realized, and the counter electrode can be adapted to various working electrode materials; the requirements of multi-system and multifunctional devices are met; meanwhile, the selected materials are high in inorganic degree, and the safety is superior to that of organic electrochromic materials.

Description

Technical Field

[0001] This invention relates to the field of electrochromic materials technology, specifically to a universal electrochromic complementary counter electrode, its preparation method, and its application method. Background Technology

[0002] Electrochromic technology, which modulates the optical properties of materials by applying an external electric field, is widely used in fields such as smart windows, dynamic displays, and optical devices. In complementary electrochromic devices, the counter electrode and the working electrode need to work in tandem, achieving a dynamic balance of the overall optical state of the device through mutually matched redox reactions. Although traditional counter electrode materials (such as WO3 and Prussian blue) can provide ion storage or limited reversible color change, their compatibility, adaptability, and universality of synergistic color change with the working electrode are still limited, making it difficult to meet the needs of multi-system, multi-functional devices.

[0003] Against this backdrop, the universal complementary electrochromic counter electrode CuI, based on a reversible conversion reaction, has gradually become a research focus. CuI is the first transparent conductive material prepared by humans (P-type, 1907), possessing extremely high transparency and environmental stability. Simultaneously, under the influence of an external electric field, CuI can be reduced to Cu to achieve a color transition from colorless and transparent to black, and can also be oxidized to I2 to achieve a color transition from colorless and transparent to dark brown. Based on this, the CuI universal complementary electrochromic counter electrode can be used as an anode and cathode electrochromic material for matching, or as a cathode and anode electrochromic material for matching, to form a complementary electrochromic device. It is worth noting that two CuI universal complementary electrochromic counter electrodes can also be used as a cathode and anode respectively, forming a complementary electrochromic device on their own. The invention of this electrode is of great significance for the development of high-performance complementary electrochromic devices. Summary of the Invention

[0004] To address the aforementioned problems, the purpose of this invention is to propose a universal electrochromic complementary counter electrode, its preparation method, and its application method. The counter electrode of this solution can function as either an anode, thus constructing a complementary electrochromic device with the cathode electrochromic electrode, or as a cathode, thus forming a complementary electrochromic device with the anode electrochromic electrode. This achieves versatility for both anode and cathode, and it can be adapted to various working electrode materials, meeting the needs of multi-system, multi-functional devices. Furthermore, the selected materials have a high degree of inorganic content and are safer than organic electrochromic materials.

[0005] This was achieved through the following technical solutions: A universal electrochromic complementary counter electrode comprises an electrochemically active material A, a conductive glass B, a binder C, and a conductive agent D. The electrochemically active material A has multiple redox couples, and the conductive glass B is used to support the active material in the electrochemically active material A. The counter electrode is used to match different electrochromic anodes / cathodes to form a complete electrochromic electrochemical system.

[0006] Optionally, electrochemically active material A is a compound possessing both oxidizing and reducing properties. Electrochemically active material A can undergo oxidation or reduction reactions depending on the voltage, and both reactions are accompanied by color changes. Electrochemically active material A acts as an anodic electrochromic material when exhibiting oxidizing properties and as a cathodic electrochromic material when exhibiting reducing properties. Conductive glass B possesses high light transmittance, conductivity, and serves as a mechanical support for the electrode pair. Binder C is the binding agent between electrochemically active material A, conductive agent D, and conductive glass B. Conductive agent D is the material providing electrical contact between electrochemically active material A and conductive glass B. Electrochemically active material A is a single compound with both oxidizing and reducing capabilities, enabling bidirectional color changes and switching roles according to voltage direction, significantly simplifying device pairing and design.

[0007] Optionally, electrochemically active substance A may simultaneously possess two or more of the following: oxidizing and reducing substances.

[0008] Optionally, the electrochemically active material A includes at least CuI or at least [CuI2]. - .

[0009] Optionally, electrochemically active material A also contains Cu + / Cu and I2 / I - It also contains Cu + The two reversible redox pairs, Cu and I₂ / I⁻, are the chemical core of the bifunctional reaction, ensuring that I₂ acts as the anode. - When oxidized and colored, Cu is used as a cathode. + The color is reduced.

[0010] Optionally, the conductive glass B is selected from a plurality of transparent conductive glasses, wherein the plurality of transparent conductive glasses include at least F-doped SnO2, indium tin oxide, and zinc aluminum oxide. Mature transparent conductive glasses such as FTO and ITO ensure the substrate is conductive, transparent, and stable, provide reliable mechanical support and charge collection interface, and are beneficial to device integration and optical performance.

[0011] Optionally, binder C is selected from polyquaternium-10, sodium alginate, and polyvinylpyrrolidone; conductive agent D is selected from indium tin oxide, carbon nanotubes, and silver nanowires.

[0012] Secondly, a preparation method is proposed for preparing the above-mentioned universal electrochromic complementary counter electrode, comprising the following steps: S1. Dissolve adhesive C in deionized water to form a clear solution; S2. Electrochemically active substance A, which has multiple redox couples, and conductive agent D are added to a clear solution and mixed evenly to obtain a mixed suspension. S3. Apply the suspension evenly onto the conductive glass B; S4. Place the coated conductive glass B in an oven to dry, and obtain a universal complementary electrochromic counter electrode. S5. When the universal complementary electrochromic electrode is used as the anode, an oxidation reaction occurs, and the coloring process is completed from colorless and transparent. When the universal complementary electrochromic electrode is used as the cathode, a reduction reaction occurs, and the coloring process is completed from colorless and transparent.

[0013] Optionally, the mass ratio of electrochemical active substance A, binder C, and conductive agent D is 2:1:3.5; and the concentration ratio of conductive agent D to electrochemical active substance A is 1.75:1.

[0014] In addition, an application method is proposed for using the above-mentioned universal electrochromic complementary counter electrode. In this application method, the counter electrode can be matched with either the anodic electrochromic material or the cathodic electrochromic material, and is used in the construction of a complementary electrochromic device.

[0015] The beneficial effects of this invention compared to the prior art are: The technical solution of this invention improves the counter electrode, which can be used as an anode to construct a complementary electrochromic device with the cathode electrochromic electrode, or as a cathode to construct a complementary electrochromic device with the anode electrochromic electrode. This achieves the versatility of the anode and cathode, and can be adapted to various working electrode materials to meet the needs of multi-system and multi-functional devices. At the same time, the selected materials have a high degree of inorganicity and are safer than organic electrochromic materials. Attached Figure Description

[0016] Figure 1 This is a flowchart of a preparation method; Figure 2 This is a schematic diagram of a universal electrochromic complementary electrode. Figure 3 This is a schematic diagram of a reaction principle. Detailed Implementation

[0017] The following will be based on embodiments of the present invention. Figure 1 , Figure 2 and Figure 3 The technical solutions in the embodiments of the present invention will be described in detail below.

[0018] like Figure 1 The diagram shown is a flowchart of a preparation method; as shown Figure 2 The diagram shown is a schematic of a universal electrochromic complementary counter electrode; combined with Figure 1 and Figure 2 As shown, the counter electrode contains electrochemically active material A, conductive glass B, binder C, and conductive agent D. This counter electrode can serve as both an anode and a cathode, achieving matching with different electrochromic anodes / cathodes. Furthermore, it exhibits a distinct color reaction during the change process, effectively forming a complete electrochromic electrochemical system.

[0019] Electrochemically active material A possesses multiple redox couples, making it a compound that simultaneously exhibits oxidizing and reducing properties. Electrochemically active material A can undergo oxidation or reduction reactions depending on the voltage, with each reaction accompanied by a color change; for example, CuI→Cu changes from transparent to black, and CuI→I2 changes from colorless to dark brown. Electrochemically active material A acts as an anodic electrochromic material when exhibiting oxidizing properties and as a cathodic electrochromic material when exhibiting reducing properties. Conductive glass B possesses high light transmittance, conductivity, and serves as a mechanical support for the electrode pairs. Binder C is the binding agent between electrochemically active material A, conductive agent D, and conductive glass B; conductive agent D is the material providing electrical contact between electrochemically active material A and conductive glass B. Electrochemically active material A is a single compound with both oxidizing and reducing capabilities, enabling bidirectional color change and switching roles according to voltage direction, significantly simplifying device pairing and design.

[0020] Furthermore, electrochemically active substance A may simultaneously possess two or more of the following: oxidizing and reducing substances, and must possess at least one oxidizing substance and one reducing substance. Electrochemically active substance A includes at least CuI or at least [CuI2]. - This ensures that the color-changing reaction can occur. Electrochemically active substance A may also contain Cu. + / Cu and I2 / I - Contains both Cu⁺ / Cu and I₂ / I₂. - Two reversible redox couples form the chemical core of the bifunctional reaction, ensuring that I₂ is present when acting as the anode. - Cu⁺ is oxidized and colored, but when used as a cathode, it is reduced and colored.

[0021] Conductive glass B is used to support the active material in electrochemically active material A. Conductive glass B is selected from a variety of transparent conductive glasses, which include at least F-doped SnO2, indium tin oxide, and zinc aluminum oxide. Mature transparent conductive glasses such as FTO and ITO ensure the substrate's conductivity, light transmission, and stability, providing reliable mechanical support and charge collection interfaces, which is beneficial for device integration and optical performance.

[0022] Binder C is selected from polyquaternium-10, sodium alginate, and polyvinylpyrrolidone; conductive agent D is selected from indium tin oxide, carbon nanotubes, and silver nanowires. The binder enhances the bonding force between components and prevents detachment; the conductive agent constructs a highly efficient conductive network and reduces resistance; together, they improve the mechanical stability and electrochemical reaction efficiency of the electrode.

[0023] Secondly, a preparation method is proposed for preparing the above-mentioned universal electrochromic complementary counter electrode, comprising the following steps: S1. Dissolve adhesive C in deionized water to form a clear solution; S2. Electrochemically active substance A, which has multiple redox couples, and conductive agent D are added to a clear solution and mixed evenly to obtain a mixed suspension. S3. Apply the suspension evenly onto the conductive glass B. The application can be done by spin coating, drop coating, scraping coating, or dip coating. (For example, a spin coating instrument can be used for 800 r / min for 9 s or 1200 r / min for 30 s.) S4. Place the coated conductive glass B in an oven to dry, and obtain a universal complementary electrochromic counter electrode. S5. When the universal complementary electrochromic electrode is used as the anode, an oxidation reaction occurs, and the coloring process is completed from colorless and transparent. When the universal complementary electrochromic electrode is used as the cathode, a reduction reaction occurs, and the coloring process is completed from colorless and transparent.

[0024] The electrochemically active material A, binder C, and conductive agent D are in a mass ratio of 2:1:3.5. This ensures both good adhesion between the electrochemically active material and the substrate (i.e., conductive glass) and electrical contact between the electrochemically active material and the conductive substrate. The concentration ratio of conductive agent D to electrochemically active material A is 1.75:1. For example, the mass of electrochemically active material A is 0.2~0.8g, the mass of binder is 0.1~0.4g, and the mass of conductive agent is 0.35~1.4g.

[0025] Exemplary, a method for preparing a universal complementary electrochromic counter electrode based on a reversible conversion reaction, combined with... Figure 1 The following steps can be taken: 1): Dissolve 0.2g of P10 (binder C) in 8 ml of deionized water to form a clear solution; 2): Add 0.4g CuI (substance A with multiple redox pairs) and 0.7g ITO (conductive agent D) to the clarified solution and mix evenly to obtain a mixed suspension; 3): The suspension is evenly coated onto FTO conductive glass (transparent conductive glass B, size less than 10×10cm) by means of spin coating, drop coating, scraping coating and dip coating; 4): The transparent conductive glass coated with the suspension is placed in an oven and dried to obtain the CuI universal complementary electrochromic counter electrode (universal complementary electrochromic counter electrode). 5): When the CuI universal complementary electrochromic electrode is used as the anode, an oxidation reaction occurs: CuI (colorless and transparent) - e - →I2 (dark brown), and changes from colorless and transparent to dark brown. When the CuI universal complementary electrochromic pair electrode is used as the cathode, the reduction reaction occurs: CuI (colorless and transparent) + e- → I2 (dark brown). - →Cu (black), and changes from colorless and transparent to black.

[0026] Exemplarily, a compatibility test was performed on the CuI universal complementary electrochromic electrode of this embodiment, combined with... Figure 2 As shown, when A is used as the anode and matched with the cathode electrochromic material tungsten trioxide (WO3), a complementary electrochromic device is constructed. In the initial state, both CuI and WO3 are colorless and transparent. When a coloring voltage is applied, WO3 is reduced to (NH4). x WO 3-x It turns blue, at which point the CuI universal complementary electrochromic electrode is oxidized to I2 and turns dark brown. When the voltage is reversed, (NH4) x WO 3-x It is oxidized to WO3 and returns to its colorless and transparent state. I2 is reduced to I. - With Cu + The CuI universal complementary electrochromic electrode was then restored to colorless and transparent.

[0027] like Figure 3 The diagram illustrates the reaction principle, showing the changes when A contains CuI and WO3. When A is used as the cathode and matched with the cathode electrochromic material Prussian white (PW) to construct a complementary electrochromic device, both CuI and PW are initially colorless and transparent. When a coloring voltage is applied, PW is oxidized to Prussian blue (PB), turning blue, while CuI is reduced to Cu, turning black. When the voltage is reversed, PB is reduced back to PW, returning to its original colorless and transparent state. Cu is oxidized to Cu... +with I - The CuI universal complementary electrochromic electrode was then restored to colorless and transparent.

[0028] Furthermore, this application proposes an application method for using the aforementioned universal electrochromic complementary counter electrode. In this method, the counter electrode can be matched with either an anode electrochromic material or a cathode electrochromic material, and is applied in the construction of a complementary electrochromic device. The beneficial effects of this application are the same as those of the aforementioned universal electrochromic complementary counter electrode, and will not be repeated here.

[0029] In summary, the improved counter electrode of this invention can function as either an anode to construct a complementary electrochromic device with the cathode electrochromic electrode, or as a cathode to construct a complementary electrochromic device with the anode electrochromic electrode. This achieves versatility for both anode and cathode, and it can be adapted to various working electrode materials to meet the needs of multi-system and multi-functional devices. Furthermore, the selected materials have a high degree of inorganicity and are safer than organic electrochromic materials, demonstrating significant advancements.

[0030] The above embodiments are merely illustrative of the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solutions based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. A universal electrochromic complementary counter electrode, characterized in that, The counter electrode comprises an electrochemically active substance A, a conductive glass B, a binder C, and a conductive agent D, the electrochemically active substance A has multiple redox couples, the conductive glass B is used to support the active substance in the electrochemically active substance A; the counter electrode is used to match different electrochromic anodes / cathodes to form a complete electrochromic electrochemical system.

2. A universal electrochromic complementary counter electrode according to claim 1, characterized in that, The electrochemically active substance A is a compound having both oxidizing and reducing substances, and the electrochemically active substance A can undergo oxidation or reduction reactions at different voltages, and the reaction process is accompanied by color change; The electrochemically active substance A, when exhibiting oxidizing property, serves as an anodic electrochromic material, and when exhibiting reducing property, serves as a cathodic electrochromic material; The conductive glass B has high light transmittance, conductivity, and is used for mechanical support of the electrode pair; The binder C is a substance that binds the electrochemically active substance A, the conductive agent D, and the conductive glass B; The conductive agent D is a substance that electrically contacts the electrochemically active substance A and the conductive glass B.

3. A universal electrochromic complementary counter electrode according to claim 1, characterized in that, The electrochemically active substance A has two or more of the oxidizing and reducing substances.

4. A universal electrochromic complementary counter electrode according to claim 1, characterized in that, at least CuI or at least [CuI2] - .

5. A universal electrochromic complementary counter electrode according to claim 1 or 2, characterized in that, The electrochemically active substance A contains Cu + / Cu and I2 / I - .

6. A universal electrochromic complementary counter electrode according to claim 1 or 2, characterized in that, The conductive glass B is selected from one of multiple transparent conductive glasses, and the multiple transparent conductive glasses at least include F-doped SnO2, indium tin oxide, and aluminum zinc oxide.

7. A universal electrochromic complementary counter electrode according to claim 1 or 2, characterized in that, The binder C is selected from one of polyquaternary ammonium salt-10, sodium alginate, and polyvinylpyrrolidone; and the conductive agent D is selected from one of indium tin oxide, carbon nanotubes, and silver nanowires.

8. A method of preparation for the preparation of a universal electrochromic complementary counter electrode according to claims 1 to 7, characterized in that, The method comprises the following steps: S1, dissolving the binder C in deionized water to form a clear solution; S2, adding the electrochemically active substance A having multiple redox couples and the conductive agent D into the clear solution and uniformly mixing to obtain a mixed suspension; S3, uniformly coating the suspension on the conductive glass B; S4, placing the coated conductive glass B in an oven for drying to obtain a universal complementary electrochromic counter electrode; S5, when the universal complementary electrochromic counter electrode serves as an anode, oxidation reaction occurs and coloration is completed from colorless transparency; when the universal complementary electrochromic counter electrode serves as a cathode, reduction reaction occurs and coloration is completed from colorless transparency.

9. A method of manufacture according to claim 8, characterised in that, The mass ratio of the electrochemically active substance A, the binder C, and the conductive agent D is 2:1:3.5; and the concentration ratio of the conductive agent D to the electrochemically active substance A is 1.75:

1.

10. An application method for applying a universal electrochromic complementary counter electrode as claimed in claims 1 to 7, characterized in that, The counter electrode can match both anodic and cathodic electrochromic materials, and is applied in the construction of complementary electrochromic devices.

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