A method for manufacturing an all-solid-state electrochromic device

Abstract

The application relates to the technical field of electrochromic technology, in particular to a preparation method of a full-solid-state electrochromic device. x The preparation method comprises the following steps: (1) sequentially preparing a bottom transparent conductive layer and a WO x An electrochromic layer is prepared on the surface of the first substrate, and a top transparent conductive layer and a nickel tungsten oxide counter electrode layer are sequentially prepared on the surface of the second substrate; (2) a weak-acid electrolyte precursor solution is coated on the surface of the WO x An electrochromic layer is prepared on the surface of the first substrate, and a top transparent conductive layer and a nickel tungsten oxide counter electrode layer are sequentially prepared on the surface of the second substrate; (2) a weak-acid electrolyte precursor solution is coated on the surface of the WO x The gel semi-cured adhesive films of the first substrate and the second substrate are pasted face to face, laminated and cured to obtain the full-solid-state electrochromic device. The application effectively improves the ionic conductivity, light modulation depth and cycle stability of the device by combining the advantages of dry and wet processes, and considers the high performance and large-scale mass production feasibility.

Description

Technical Field

[0001] This invention relates to the field of electrochromic technology, and more particularly to a method for preparing an all-solid-state electrochromic device. Background Technology

[0002] Currently, there are two main process technology routes for fabricating all-solid-state electrochromic devices in the industry: dry physical vapor deposition and wet laminated adhesive process.

[0003] The all-dry process primarily employs continuous magnetron sputtering physical vapor deposition, sequentially depositing all functional thin films—including a transparent conductive layer, an electrochromic layer, an inorganic solid electrolyte layer, and an ion storage layer—in a vacuum environment. This is currently the mainstream approach for fabricating high-performance electrochromic devices. While this process can produce dense electrode functional layers with good film uniformity, it is limited by the characteristics of magnetron sputtering, making it difficult to fabricate thick inorganic solid electrolyte layers. Conventional deposition thicknesses are relatively thin, resulting in insufficient lithium-ion storage capacity within the device and significantly reducing its long-term cycle stability and deep dimming performance. Furthermore, the fabrication efficiency of high-quality, dense electrolyte films is extremely low, significantly increasing device production costs and hindering large-scale industrial application.

[0004] Another mainstream wet lamination process involves pre-fabricating two independent electrode glass substrates, then using a pre-formed polymer film as a solid electrolyte interlayer, and finally completing the device fabrication through thermo-pressing. Some processes also employ a method of filling the gap between the electrode glasses with liquid electrolyte before encapsulation. However, the liquid electrolyte filling process requires extremely high encapsulation precision, has a complex process flow, and is prone to leakage during long-term device use, resulting in poor reliability and its gradual obsolescence in the industry. While the thermo-pressing process using commercially available pre-formed polymer films such as PVB and EVA simplifies the fabrication process and avoids the risk of leakage, these commercially available polymer films themselves have extremely low ionic conductivity, only reaching 10. -7 ~10 -5 The S / cm ratio is insufficient to meet the performance requirements of rapid color change and efficient dimming in electrochromic devices. Furthermore, the adhesion between the adhesive film and the electrode surface is merely a simple physical bond without effective bonding, resulting in numerous microscopic voids between layers, extremely high interfacial contact impedance, and poor ion coupling and transport. Ultimately, this leads to poor overall electrochemical performance, hysteresis, and poor dimming uniformity. In addition, conventional polymer adhesive films have extremely low active ion content, relying excessively on the electrode layer for ion supply during operation, further limiting the device's efficiency and cycle life.

[0005] In summary, existing dry fabrication processes suffer from insufficient ion storage capacity, while traditional wet lamination processes exhibit drawbacks such as low electrolyte ion conductivity, poor interfacial contact, and weak overall device performance. Neither of these mainstream processes can simultaneously achieve excellent interfacial contact, high ion transport and storage performance, and efficient, low-cost mass production. Therefore, optimizing the fabrication process of all-solid-state electrochromic devices, while considering the electrochemical activity of the electrode layer, the ion conduction and storage capacity of the electrolyte layer, and the interfacial bonding performance, is a pressing technical problem to be solved in this field. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention utilizes a dry-wet hybrid lamination process, combining the advantages of both dry and wet fabrication methods. This process enables the fabrication of thick electrolyte layers, ensuring a good interfacial bond between the electrolyte layer and the electrode layer. Simultaneously, it balances the high-performance requirements of the device with the feasibility of large-scale mass production, effectively solving the problems of insufficient ion storage capacity, low ion conductivity, and poor interfacial contact in existing technologies.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] This invention provides a method for fabricating an all-solid-state electrochromic device, comprising the following steps:

[0009] (1) A bottom transparent conductive layer and a WO layer are sequentially prepared on the surface of the first substrate. x An electrochromic layer is formed by sequentially fabricating a top transparent conductive layer and a nickel-tungsten oxide counter electrode layer on the surface of a second substrate.

[0010] (2) In WO x A weakly acidic electrolyte precursor solution is coated on the surface of the electrochromic layer, and a weakly alkaline electrolyte precursor solution is coated on the surface of the nickel-tungsten oxide counter electrode layer. After pre-curing treatment, a gel-state semi-cured film is formed.

[0011] (3) The gel-state semi-cured adhesive films of the first substrate and the second substrate are laminated face to face and cured to obtain an all-solid-state electrochromic device.

[0012] The bottom transparent conductive layer of this invention, WO x The electrochromic layer, the top transparent conductive layer, and the nickel-tungsten oxide counter electrode layer were all prepared by magnetron sputtering deposition. Each layer surface was coated with an electrolyte precursor solution adapted to its surface characteristics, and after pre-curing, a viscous and malleable gel-like semi-cured film was formed. This film could be laminated and cured to achieve a stable bond between the upper and lower electrode substrates. The electrolyte layer, prepared using a wet process, ensured sufficient ion storage capacity and effectively improved ion conductivity due to good interlayer bonding. Meanwhile, the other electrochromic functional layers deposited by magnetron sputtering remained dense, uniform, and exhibited excellent performance.

[0013] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0014] The bottom transparent conductive layer and the top transparent conductive layer of the present invention can be ITO thin film or FTO thin film commonly used in the art. The first substrate and the second substrate can be glass with a thickness of 5.0~10.0mm, for example, 5.0mm, 6.2mm, 7.5mm, 8.8mm or 10.0mm.

[0015] Magnetron sputtering deposition to prepare the underlying transparent conductive layer, WO x The process parameters for the electrochromic layer, the top transparent conductive layer, and the nickel-tungsten oxide counter electrode layer are as follows:

[0016] A bottom transparent conductive layer is deposited on the surface of the first substrate. The deposition power density is 2~5 kW / m, for example, it can be 2 kW / m, 2.8 kW / m, 3.6 kW / m, 4.4 kW / m or 5 kW / m, etc. The deposition temperature is 200~300℃, for example, it can be 200℃, 225℃, 250℃, 275℃ or 300℃, etc. The oxygen volume concentration is 0.5%~2%, for example, it can be 0.5%, 0.9%, 1.3%, 1.7% or 2%, etc. The deposition thickness is 80~150 nm, for example, it can be 80 nm, 100 nm, 120 nm, 130 nm or 150 nm, etc.

[0017] WO3 is plated on the surface of the bottom transparent conductive layer x The electrochromic layer has a power density of 10~20 kW / m, such as 10 kW / m, 12.5 kW / m, 15 kW / m, 17.5 kW / m or 20 kW / m, etc., a coating temperature of 100~180℃, such as 100℃, 120℃, 140℃, 160℃ or 180℃, etc., an oxygen volume concentration of 5%~12%, such as 5%, 7%, 9%, 10% or 12%, etc., and a deposition thickness of 200~400 nm, such as 200 nm, 250 nm, 300 nm, 350 nm or 400 nm, etc.

[0018] A top transparent conductive layer is deposited on the surface of the second substrate. The deposition power density is 2~5 kW / m, for example, 2 kW / m, 2.7 kW / m, 3.4 kW / m, 4.1 kW / m or 5 kW / m, etc. The deposition temperature is 200~300℃, for example, 200℃, 220℃, 250℃, 270℃ or 300℃, etc. The oxygen volume concentration is 0.5%~2%, for example, 0.5%, 1.0%, 1.2%, 1.5% or 2%, etc. The deposition thickness is 80~150 nm, for example, 80 nm, 100 nm, 120 nm, 140 nm or 150 nm, etc.

[0019] A nickel-tungsten oxide counter electrode layer is deposited on the surface of the top transparent conductive layer, with a power density of 3~6 kW / m, for example, 3 kW / m, 4 kW / m, 5 kW / m or 6 kW / m, etc., a deposition temperature of 120~200℃, for example, 120℃, 140℃, 160℃, 180℃ or 200℃, etc., an oxygen volume concentration of 20%~50%, for example, 20%, 30%, 35%, 40% or 50%, etc., and a deposition thickness of 100~300 nm, for example, 100 nm, 150 nm, 200 nm, 250 nm or 300 nm, etc.

[0020] As a preferred technical solution of the present invention, the pH of the weakly acidic electrolyte precursor solution is 4.5~6.5, for example, it can be 4.5, 5.0, 5.5, 6.0 or 6.5, etc., and the pH of the weakly alkaline electrolyte precursor solution is 7.5~9.0, for example, it can be 7.5, 8.0, 8.5, 8.8 or 9.0, etc.

[0021] This invention targets WO x The surface properties of the electrochromic layer and the nickel-tungsten oxide counter electrode layer are respectively matched with weakly acidic and weakly alkaline electrolyte precursor solutions. x Electrochromic layers typically possess hydroxyl groups and oxygen vacancies on their surface, exhibiting better chemical stability in acidic environments. Weakly acidic precursor solutions can effectively prevent the formation of WO3. x Despite dissolution and structural damage under alkaline conditions, the nickel-tungsten oxide electrode layer can maintain its electrochemical activity and structural stability in a weakly alkaline environment. The weakly alkaline precursor solution can also promote the cation exchange reaction on the surface of the nickel-tungsten oxide electrode layer, which helps the reversible insertion and extraction of lithium ions. This improves the chemical compatibility between the electrolyte precursor solution and the corresponding electrode surface, achieving full wetting and interfacial bonding on the electrode surface, reducing interfacial contact resistance, and improving interfacial bonding stability.

[0022] In the WOx electrochromic layer of this invention, WOx is non-stoichiometric tungsten oxide, 2.2 ≤ x < 3.0, and the chemical formula of the tungsten-nickel oxide in the nickel-tungsten oxide counter electrode layer is WNiO. y , 0.8≤y≤2.2.

[0023] As a preferred technical solution of the present invention, the wet film thickness of the weakly acidic electrolyte precursor solution and the weakly alkaline electrolyte precursor solution is independently 50~200μm, for example, it can be 50μm, 100μm, 150μm, 180μm or 200μm, etc.

[0024] Preferably, the coating is performed using a slot coating method.

[0025] This invention controls the thickness of the electrolyte layer after curing by controlling the thickness of the wet film coated with the electrolyte precursor solution, ensuring that the electrolyte layer has sufficient thickness to store enough active lithium ions, thereby improving the device's ion storage capacity, enhancing deep dimming performance and long-term cycling stability.

[0026] As a preferred technical solution of the present invention, the weakly acidic electrolyte precursor solution is an electrolyte precursor solution with added acidity regulator, the acidity regulator including acetic acid, and the amount of added acetic acid is 0.1~0.5wt%, for example, it can be 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt% or 0.5wt%, etc.

[0027] As a preferred embodiment of the present invention, the weakly alkaline electrolyte precursor solution is an electrolyte precursor solution with added alkaline regulator, wherein the alkaline regulator includes triethylamine or ethanolamine.

[0028] When the alkalinity regulator includes triethylamine, the amount of triethylamine added is 0.2~0.8 wt%, for example, it can be 0.2 wt%, 0.35 wt%, 0.5 wt%, 0.65 wt%, or 0.8 wt%, etc.; or, when the alkalinity regulator includes ethanolamine, the amount of ethanolamine added is 0.1~0.5 wt%, for example, it can be 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, or 0.5 wt%, etc.

[0029] In this application, the electrolyte precursor solution is a commonly used electrolyte precursor solution in electrochromic devices that is well known to those skilled in the art, and can also be adapted according to the actual process.

[0030] Preferably, the electrolyte precursor solution comprises: a polymer matrix, a lithium salt, a plasticizer, a crosslinking agent, and a solvent.

[0031] Preferably, the polymer matrix comprises polyvinyl butyral (PVB) or polyethylene oxide (PEO), and the plasticizer, crosslinking agent and solvent can be selected from commonly used reagents in the art. The plasticizer includes, but is not limited to, propylene carbonate, the crosslinking agent includes, but is not limited to, glutaraldehyde, and the solvent includes, but is not limited to, N-methylpyrrolidone.

[0032] Preferably, the lithium salt comprises lithium bis(trifluoromethanesulfonylimide) (LiTFSI, CAS No.: 90076-65-6).

[0033] Preferably, by weight, the electrolyte precursor solution comprises: 10-20 parts of polymer matrix, for example, 10, 12, 15, 18 or 20 parts; 2-8 parts of lithium salt, for example, 2, 4, 6 or 8 parts; 3-10 parts of plasticizer, for example, 3, 5, 7, 9 or 10 parts; 0.5-3 parts of crosslinking agent, for example, 0.5, 1, 1.5, 2 or 3 parts; and 60-85 parts of solvent, for example, 60, 65, 70, 75 or 85 parts.

[0034] As a preferred technical solution of the present invention, the pre-curing treatment includes heating, the heating temperature is 80~120℃, for example, 80℃, 90℃, 100℃, 110℃ or 120℃, etc., and the heating time is 5~15min, for example, 5min, 8min, 10min, 12min or 15min, etc.

[0035] Preferably, the heating is performed on a heating platform.

[0036] This invention controls the pre-curing temperature and time to evaporate most of the solvent in the electrolyte precursor solution, while triggering a partial cross-linking reaction to form a gel-state semi-cured film with viscosity and plasticity. This avoids the problem of the film failing to achieve interface fusion after complete curing, and also avoids the problem of excessive fluidity of the uncured precursor solution leading to glue overflow and uneven thickness during lamination. It solves the problems of poor interface fusion and difficulty in controlling thickness uniformity of the film during lamination.

[0037] As a preferred technical solution of the present invention, the lamination and curing are carried out under vacuum conditions, wherein the pressure of the vacuum conditions is <100Pa.

[0038] Preferably, the gel-state semi-cured adhesive films of the first substrate and the second substrate are bonded face-to-face on a precision alignment stage, and alignment with micron-level precision is achieved by an optical CCD system.

[0039] As a preferred technical solution of the present invention, the lamination curing temperature is 130~180℃, for example, it can be 130℃, 145℃, 160℃, 170℃ or 180℃, etc.

[0040] As a preferred technical solution of the present invention, the lamination and curing pressure is 0.5~1.5MPa, for example, it can be 0.5MPa, 0.8MPa, 1.0MPa, 1.2MPa or 1.5MPa, etc.

[0041] As a preferred technical solution of the present invention, the lamination curing time is 10~30min, for example, it can be 10min, 15min, 20min, 25min or 30min.

[0042] The lamination and curing process of this invention uses temperature control to simultaneously trigger the complete reaction of the crosslinking agent during lamination, while avoiding damage to other layers. It achieves close contact under vacuum conditions, removes any residual micro-bubbles, and ensures complete curing of the electrolyte layer during curing time. This allows the electrolyte layer to form a stable physical and chemical bond with the electrochromic functional layers on both sides. The electrolyte layer forming process, interface bonding optimization process, and overall device encapsulation are completed simultaneously.

[0043] As a preferred embodiment of the present invention, the ionic conductivity of the prepared all-solid-state electrochromic device is ≥2×10⁻⁶. -4 S / cm, optical modulation range ≥60%, performance degradation rate ≤8% after 10,000 cycles.

[0044] Compared with the prior art, the present invention has at least the following beneficial effects:

[0045] (1) The present invention combines the advantages of high electrochemical activity of dry electrode preparation and high ionic conductivity and large ion storage capacity of wet electrolyte preparation through a dry-wet mixing process. The device prepared has excellent cycle stability and deep dimming performance.

[0046] (2) This invention achieves a tight bond between the electrolyte layer and the electrode layer by combining the electrolyte precursor liquid adaptation, pre-cured gel film preparation and vacuum hot pressing lamination process, eliminating interface contact defects and significantly reducing ion transport impedance. At the same time, the preparation process is simple and compatible with existing glass processing coating lines and laminating equipment, and has the prospect of large-scale industrial application. Detailed Implementation

[0047] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0048] Example 1

[0049] This embodiment provides a method for fabricating an all-solid-state electrochromic device, the steps of which are as follows:

[0050] (1) A glass with a thickness of 6 mm was selected as the first substrate and the second substrate; an ITO bottom transparent conductive layer was prepared by magnetron sputtering on the surface of the first substrate: power density 3 kW / m, coating temperature 250 ℃, coating pressure 0.5 Pa, oxygen volume concentration 1%, and deposition thickness 120 nm; WO3 was prepared by magnetron sputtering on the surface of the bottom transparent conductive layer. xElectrochromic layer: power density 15kW / m, coating temperature 150℃, coating pressure 1.0Pa, oxygen volume concentration 8%, deposition thickness 300nm; ITO top transparent conductive layer prepared by magnetron sputtering on the surface of the second substrate: parameters are the same as the bottom transparent conductive layer; Nickel-tungsten oxide counter electrode layer prepared by magnetron sputtering on the surface of the top transparent conductive layer: power density 5kW / m, coating temperature 150℃, coating pressure 1.0Pa, oxygen volume concentration 20%, deposition thickness 200nm;

[0051] (2) Preparation of electrolyte precursor solution: including 15 parts PVB (molecular weight 80,000), 5 parts LiTFSI, 6 parts plasticizer (propylene carbonate), 1.5 parts crosslinking agent (glutaraldehyde), and 72.5 parts solvent (N-methylpyrrolidone), stirred at 60°C until completely dissolved, filtered and degassed for later use; 0.3 wt% acetic acid was added to the above electrolyte precursor solution to obtain a weakly acidic electrolyte precursor solution with pH=5.5, which was coated on WO3 using the slit coating method. x The electrochromic layer surface has a wet film thickness of 100 μm. 0.5 wt% triethylamine is added to the above electrolyte precursor solution to obtain a weakly alkaline electrolyte precursor solution with pH=8.0. The precursor solution is coated on the surface of the nickel tungsten oxide counter electrode layer using the slit coating method, with a wet film thickness of 100 μm. The two substrates are placed on a heating platform at 100°C for 10 min to pre-cur them and form a gel-state semi-cured film.

[0052] (3) The two substrate films are placed face to face on a precision alignment stage and aligned at the micron level by optical CCD; they are then sent into a vacuum laminator and hot-pressed for 20 minutes at 150°C and 1.0MPa under a vacuum environment with a pressure of <100Pa to complete the curing and encapsulation.

[0053] Example 2

[0054] This embodiment provides a method for fabricating an all-solid-state electrochromic device, the steps of which are as follows:

[0055] (1) Using the same parameters as in Example 1, a bottom transparent conductive layer and a WO layer were sequentially prepared on the surface of the first substrate. x An electrochromic layer is formed by sequentially fabricating a top transparent conductive layer and a nickel-tungsten oxide counter electrode layer on the surface of a second substrate.

[0056] (2) Preparation of electrolyte precursor solution: including 10 parts PVB (molecular weight 80,000), 2 parts LiTFSI, 3 parts plasticizer (propylene carbonate), 0.5 parts crosslinking agent (glutaraldehyde), and 60 parts solvent (N-methylpyrrolidone), stirred at 60°C until completely dissolved, filtered and degassed for later use; add 0.5 wt% acetic acid to the electrolyte precursor solution to obtain a weakly acidic electrolyte precursor solution with pH=4.5, and coat it on WO3 using the slit coating method. xThe electrochromic layer surface has a wet film thickness of 50 μm; 0.8 wt% triethylamine is added to the above electrolyte precursor solution to obtain a weakly alkaline electrolyte precursor solution with pH=9.0, which is coated on the surface of the nickel tungsten oxide counter electrode layer using the slit coating method, with a wet film thickness of 50 μm; the two substrates are placed on an 80℃ heating platform for pre-curing for 5 min to form a gel-state semi-cured film.

[0057] (3) The two substrate films are placed face to face on a precision alignment stage and aligned at the micron level by optical CCD; then they are sent into a vacuum laminator and hot-pressed for 10 minutes at 130°C and 0.5MPa under a vacuum environment with a pressure of <100Pa to complete the curing and encapsulation.

[0058] Example 3

[0059] This embodiment provides a method for fabricating an all-solid-state electrochromic device, the steps of which are as follows:

[0060] (1) Using the same parameters as in Example 1, a bottom transparent conductive layer and a WO layer were sequentially prepared on the surface of the first substrate. x An electrochromic layer is formed by sequentially fabricating a top transparent conductive layer and a nickel-tungsten oxide counter electrode layer on the surface of a second substrate.

[0061] (2) Preparation of electrolyte precursor solution: including 20 parts PVB (molecular weight 80,000), 8 parts LiTFSI, 10 parts plasticizer (propylene carbonate), 3 parts crosslinking agent (glutaraldehyde), and 85 parts solvent (N-methylpyrrolidone), stirred at 60°C until completely dissolved, filtered and degassed for later use; 0.1 wt% acetic acid was added to the electrolyte precursor solution to obtain a weakly acidic electrolyte precursor solution with pH=6.5, which was coated onto WO3 using the slit coating method. x The electrochromic layer surface has a wet film thickness of 200 μm. 0.2 wt% triethylamine is added to the above electrolyte precursor solution to obtain a weakly alkaline electrolyte precursor solution with pH=7.5. The precursor solution is coated on the surface of the nickel tungsten oxide counter electrode layer using the slit coating method, with a wet film thickness of 200 μm. The two substrates are placed on a heating platform at 120°C for 15 min to pre-cur and form a gel-state semi-cured film.

[0062] (3) The two substrate films are placed face to face on a precision alignment stage and aligned at the micron level by optical CCD; then they are sent into a vacuum laminator and hot-pressed for 30 minutes at 180°C and 1.5MPa under a vacuum environment with a pressure of <100Pa to complete the curing and encapsulation.

[0063] Example 4

[0064] This embodiment provides a method for preparing an all-solid-state electrochromic device. Except for the pre-curing heating temperature of 70°C, the rest is the same as in Example 1.

[0065] Example 5

[0066] This embodiment provides a method for preparing an all-solid-state electrochromic device. Except for the pre-curing heating temperature of 130°C, the rest is the same as in Example 1.

[0067] Comparative Example 1

[0068] This comparative example provides a method for fabricating an all-solid-state electrochromic device, which is coated on WO3. x Acetic acid was not added to the electrolyte precursor solution on the surface of the electrochromic layer, and triethylamine was not added to the electrolyte precursor solution coated on the surface of the nickel-tungsten oxide counter electrode layer; all other aspects were the same as in Example 1.

[0069] Comparative Example 2

[0070] This comparative example provides a method for preparing an all-solid-state electrochromic device. Step (1) is the same as in Example 1. The same weakly acidic electrolyte precursor solution as in Example 1 is used. The slit coating method is used to coat the WOx electrochromic layer surface, and the wet film thickness is 200 μm. The semi-solid adhesive film is obtained by pre-curing on a heating platform at 100°C for 10 min. The second substrate with the top transparent conductive layer and the nickel tungsten oxide counter electrode layer is placed on the semi-solid adhesive film attached to the first substrate on a precision alignment stage. Micron-level alignment is completed by optical CCD. The device is sent to a vacuum laminator and hot-pressed at 150°C and 1.0 MPa for 20 min under a vacuum environment with a pressure of <100 Pa to complete the curing and encapsulation.

[0071] Comparative Example 3

[0072] This comparative example provides a method for fabricating an all-solid-state electrochromic device. Using the same parameters as in Example 1, a bottom transparent conductive layer and a WOx electrochromic layer are sequentially fabricated on the surface of a first substrate. The same weakly acidic electrolyte precursor solution as in Example 1 is used to coat the WOx electrochromic layer surface using a slot coating method, resulting in a wet film thickness of 200 μm. The substrate is then cured at 150°C for 60 min to obtain an electrolyte layer. A nickel-tungsten oxide counter electrode layer and a top transparent conductive layer are fabricated on the surface of the electrolyte layer using magnetron sputtering. Finally, the substrate is encapsulated using UV curing.

[0073] Test method:

[0074] The all-solid-state electrochromic devices prepared in the examples and comparative examples were subjected to performance tests. The ionic conductivity, optical modulation range, and cycle stability of the devices were tested in an environment of 25°C and 50% relative humidity. Specific tests included:

[0075] (1) Ionic conductivity test: The ionic conductivity was obtained by AC impedance spectroscopy. The cured electrolyte membrane was assembled into a stainless steel blocked electrode symmetrical cell and tested at 25°C.

[0076] (2) Optical modulation range test: The average transmittance of the visible light spectrum from 380 to 780 nm was tested. Stable transmittance values ​​of the device in the fully bleached state and the fully colored state were collected respectively. The difference between the two values ​​is the visible light optical modulation range.

[0077] (3) Cyclic stability test: A continuous electrochemical cycle was performed with +2.0V coloring for 30s and -2.0V bleaching for 30s as one complete cycle. The modulation amplitude was recorded once every 1000 cycles during the test. After 10,000 cycles, the optical modulation range of the device was tested, and the performance degradation rate after cycling was calculated. Performance degradation rate = (initial optical modulation range - optical modulation range after cycling) / initial optical modulation range × 100%.

[0078] The test results are shown in Table 1.

[0079] Table 1

[0080] Example 1 <![CDATA[2.8×10 -4 ]]> 68 5.2 Example 2 <![CDATA[2.1×10 -4 ]]> 62 7.8 Example 3 <![CDATA[2.5×10 -4 ]]> 65 6.3 Example 4 <![CDATA[8.5×10 -5 ]]> 52 16.5 Example 5 <![CDATA[6.2×10 -5 ]]> 48 22.3 Comparative Example 1 <![CDATA[4.5×10 -5 ]]> 45 28.6 Comparative Example 2 <![CDATA[3.8×10 -5 ]]> 40 32.4 Comparative Example 3 <![CDATA[2.1×10 -5 ]]> 42 38.5

[0081] The test results show that:

[0082] (1) As can be seen from Examples 1 to 3, the all-solid-state electrochromic device prepared by the present invention through a combination of differential pH electrolyte precursor solution adaptation, pre-cured gel film and vacuum hot pressing lamination process can achieve 2.1 × 10 -4 ~2.8×10 -4 With an ionic conductivity of S / cm, a visible light optical modulation range of 62%~68%, and a low cycling performance decay rate of 5.2%~7.8%, the overall performance is stable and meets the requirements for high-performance electrochromic devices.

[0083] (2) As can be seen from Examples 1 and 4-5, by controlling the pre-curing heating temperature within the range of 80-120°C, the present invention can achieve sufficient evaporation and moderate cross-linking of the electrolyte precursor solvent, forming a semi-cured film with both viscosity and plasticity, and obtaining the best interface bonding effect and performance. Too low a pre-curing temperature (70°C) leads to solvent residue and insufficient cross-linking; too high a pre-curing temperature (130°C) leads to excessive solvent evaporation, film cracking, and excessive cross-linking, resulting in loss of viscosity, all of which significantly reduce the performance of the device.

[0084] (3) As can be seen from Example 1 and Comparative Example 1, the present invention can effectively improve the chemical compatibility between the electrolyte and the electrode surface by matching electrolyte precursor solutions with different pH values ​​for the two electrodes, thereby reducing interfacial contact impedance and improving ion transport efficiency. As can be seen from Example 1 and Comparative Example 2, when electrolyte is coated on only one side of the electrode and then laminated, problems such as poor interfacial bonding and poor electrolyte thickness uniformity occur, leading to a decrease in device performance. As can be seen from Example 1 and Comparative Example 3, the present invention uses a dry-wet mixing process of preparing two electrodes separately and then laminating them together to achieve a tight bond between the electrolyte and the electrode, significantly reducing interfacial impedance and improving cycle stability. When using a layer-by-layer preparation process of first curing the electrolyte and then sputtering the upper electrode, problems such as uneven electrolyte surface, poor sputtering coating effect, and poor interfacial bonding occur.

[0085] In summary, this invention effectively solves the problems of insufficient ion storage capacity, low ion conductivity, and poor interfacial contact in existing technologies by using a dry-wet mixing lamination process, combined with differentiated pH electrolyte precursor solution adaptation, pre-cured gel film preparation, and vacuum hot pressing lamination techniques. This achieves a balance between high device performance and the feasibility of mass production processes.

[0086] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for fabricating an all-solid-state electrochromic device, characterized in that, Includes the following steps: (1) A bottom transparent conductive layer and a WO layer are sequentially prepared on the surface of the first substrate. x An electrochromic layer is formed by sequentially fabricating a top transparent conductive layer and a nickel-tungsten oxide counter electrode layer on the surface of a second substrate. (2) In WO x A weakly acidic electrolyte precursor solution is coated on the surface of the electrochromic layer, and a weakly alkaline electrolyte precursor solution is coated on the surface of the nickel-tungsten oxide counter electrode layer. After pre-curing treatment, a gel-state semi-cured film is formed. (3) The gel-state semi-cured adhesive films of the first substrate and the second substrate are laminated face to face and cured to obtain an all-solid-state electrochromic device.

2. The preparation method according to claim 1, characterized in that, The pH of the weakly acidic electrolyte precursor solution is 4.5~6.5, and the pH of the weakly alkaline electrolyte precursor solution is 7.5~9.

0.

3. The preparation method according to claim 1, characterized in that, The wet film thickness of the weakly acidic electrolyte precursor solution and the weakly alkaline electrolyte precursor solution is independently 50~200μm.

4. The preparation method according to claim 1, characterized in that, The weakly acidic electrolyte precursor solution is an electrolyte precursor solution with added acidity regulator, the acidity regulator including acetic acid, and the amount of acetic acid added is 0.1~0.5wt%.

5. The preparation method according to claim 1, characterized in that, The weakly alkaline electrolyte precursor solution is an electrolyte precursor solution with added alkaline regulators, including triethylamine or ethanolamine. When the alkalinity regulator includes triethylamine, the amount of triethylamine added is 0.2~0.8 wt%; or, when the alkalinity regulator includes ethanolamine, the amount of ethanolamine added is 0.1~0.5 wt%.

6. The preparation method according to claim 1, characterized in that, The pre-curing process includes heating, the heating temperature being 80~120℃, and the heating time being 5~15min.

7. The preparation method according to claim 1, characterized in that, The lamination and curing are carried out under vacuum conditions, where the pressure of the vacuum conditions is <100 Pa.

8. The preparation method according to claim 1, characterized in that, The lamination and curing temperature is 130~180℃.

9. The preparation method according to claim 1, characterized in that, The lamination and curing pressure is 0.5~1.5MPa.

10. The preparation method according to claim 1, characterized in that, The lamination curing time is 10~30 minutes.