Preparation method of a hydrated co-crystal polymer electrolyte and application thereof in preparation of a solid-state electrochromic device

Abstract

The application relates to a preparation method of a hydrated eutectic polymer electrolyte and application thereof in preparation of a solid-state electrochromic device, and belongs to the preparation field of electrochromic materials and devices. The application aims to solve the problems of poor stability, insufficient ionic conductivity, poor mechanical performance and packaging difficulty of the electrolyte used in the existing electrochromic device. The method comprises the following steps: I. weighing a eutectic solvent, a lithium salt, water, a photocuring monomer, a photocuring crosslinking agent and a photoinitiator to obtain a hydrated eutectic polymer electrolyte composition; II. mixing and curing to obtain the hydrated eutectic polymer electrolyte. The application applies the in-situ curing method to assemble the electrochromic device, simplifies the preparation process of the device and can realize low interface impedance; the prepared solid-state electrochromic device has high transmittance modulation amplitude, fast color change response and over-cycling life.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of preparation of electrochromic materials and devices, and particularly relates to a preparation method of a hydrated eutectic polymer electrolyte and application thereof in preparation of a solid-state electrochromic device. BACKGROUND

[0002] Electrochromism is a phenomenon that the photoelectric properties of a material change stably and reversibly under an applied electric field. At present, electrochromic technology has attracted more and more attention in the application fields of intelligent building windows, automobile canopies, anti-dazzling rearview mirrors, information display and flexible electronics. A typical electrochromic device is composed of five layers, i.e. two transparent conductive layers, an electrochromic layer (working electrode layer), an electrolyte layer and a counter electrode layer. The electrolyte layer, which is located between the upper and lower electrodes of the device, is an important component of the device, and it plays a role in transporting ions, balancing charges and blocking electrons.

[0003] Although the commonly used organic liquid electrolyte has high ionic conductivity, it is flammable, volatile and toxic, and has a great safety hazard. Although the aqueous electrolyte is safe and non-toxic, its narrow electrochemical window limits its application. The eutectic electrolyte is formed based on the interactions of intermolecular hydrogen bonds, Lewis acid-base and van der Waals forces, and it has the advantages of low vapor pressure, high thermal stability and chemical stability, and non-flammability. As a new type of electrolyte system, the hydrated eutectic electrolyte is formed by introducing a small amount of water molecules into the eutectic electrolyte system, and it has the advantages of both aqueous electrolyte and eutectic electrolyte. First, as a strong polar molecule, the introduction of water molecules reduces the viscosity of the original eutectic electrolyte and improves the limited ionic conductivity of the eutectic electrolyte. Second, in the hydrated eutectic electrolyte, water molecules form stable hydrogen bonds with eutectic electrolyte molecules, the hydrogen bond network between water molecules is broken, and the activity of free water is reduced, thus maintaining the wide voltage window characteristics of the original eutectic electrolyte. Finally, the protons and hydroxide ions produced by the ionization of water molecules can improve the charge capacity of the electrochromic electrode material. However, the above-mentioned electrolytes have the problems of leakage and difficulty in packaging in practical application. Although the use of inorganic solid-state electrolyte can well solve the problems of electrolyte leakage and device packaging, its low ionic conductivity, brittleness and serious interface problems seriously limit its application. SUMMARY

[0004] The purpose of the present application is to solve the problems of poor stability, insufficient ionic conductivity, poor mechanical properties and packaging difficulty of the electrolyte used in the existing electrochromic device, and to provide a preparation method of a hydrated eutectic polymer electrolyte and application thereof in preparation of a solid-state electrochromic device.

[0005] A preparation method of a hydrated eutectic polymer electrolyte, which is specifically completed according to the following steps:

[0006] 1. Weighing a eutectic solvent, a lithium salt, water, a photocurable monomer, a photocurable crosslinker, and a photoinitiator to obtain a hydrated eutectic polymer electrolyte composition;

[0007] The eutectic solvent in step 1 is one or more of acetamide, N-methylacetamide, urea, methylurea, tetramethylurea, trifluoroacetamide, N-methyltrifluoroacetamide, 1,2-dimethylimidazole and sulfolane;

[0008] The lithium salt described in step 1 is one or more of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorooxalatoborate), lithium trifluoromethanesulfonate, lithium tetrafluoroborate, lithium perchlorate, lithium nitrate and lithium chloride;

[0009] 2. Under light-proof conditions, mix the eutectic solvent, lithium salt, water, photocurable monomer, photocurable crosslinker and photoinitiator weighed in step 1, stir evenly, and let it stand for a period of time to obtain an unpolymerized electrolyte precursor; pour the unpolymerized electrolyte precursor into a silicone mold, and then cure it under ultraviolet light for a period of time to obtain a hydrated eutectic polymer electrolyte.

[0010] A hydrated eutectic polymer electrolyte is used in the preparation of solid-state electrochromic devices.

[0011] Principle of the present invention:

[0012] The present invention provides a method for preparing a hydrated eutectic polymer electrolyte and applies it to an electrochromic device; the hydrated eutectic-based polymer electrolyte uses an aqueous eutectic electrolyte as a mobile phase and a polymer network as a stationary phase, and the mobile phase is dispersed in the network of the stationary phase through intermolecular interactions. The hydrated eutectic-based polymer electrolyte designed in this way has considerable ionic conductivity, high thermal stability and electrochemical stability, and excellent mechanical properties; in addition, the electrochromic device is prepared by an in-situ photocuring method, mainly by designing the polymer network to be capable of being polymerized by a photocurable monomer (containing at least one hydrogen bond-rich monomer), a crosslinker, and a photoinitiator under ultraviolet light. This method can simultaneously realize the formation of the polymer electrolyte and the assembly of the device, so that good interface contact and strong interface stability can be obtained. In short, the electrolyte design and preparation method of the present invention provides a novel technical strategy for high-performance electrochromic devices.

[0013] Compared with the prior art, the present invention has the following technical effects:

[0014] 1. The present invention uses a hydrated eutectic electrolyte as the mobile phase of the polymer electrolyte. The hydrated eutectic electrolyte combines the advantages of aqueous electrolytes and eutectic electrolytes, so that the polymer electrolyte based on the hydrated eutectic has high ionic conductivity and a wide electrochemical stability window;

[0015] 2. The present invention uses a polymer network formed by a polymer monomer rich in hydrogen bonds, which makes the electrolyte have high mechanical strength and excellent bonding properties;

[0016] 3. The present invention adopts an in-situ curing method to assemble the electrochromic device, which simplifies the device preparation process and can achieve low interface impedance;

[0017] 4. The solid-state electrochromic device prepared by the present invention has a high transmittance modulation amplitude, a relatively fast color change response and a cycle life exceeding 100%. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 These are digital photos of the solid-state electrochromic device based on the hydrated eutectic polymer electrolyte prepared in Example 1 in the colored state and the faded state;

[0019] Figure 2 1 is the transmittance curve of the solid-state electrochromic device based on the hydrated eutectic polymer electrolyte prepared in Example 1 in the colored state and the faded state;

[0020] Figure 3 This is a graph showing the response speed of the solid-state electrochromic device based on the hydrated eutectic polymer electrolyte prepared in Example 1 during the coloring and fading processes;

[0021] Figure 4 Transmittance curves of the solid-state electrochromic device prepared in Comparative Example 1 in the colored state and the faded state;

[0022] Figure 5 These are the transmittance curves of the solid-state electrochromic device prepared in Example 1 in the colored state and the faded state. DETAILED DESCRIPTION

[0023] Specific embodiment 1: This embodiment provides a method for preparing a hydrated eutectic polymer electrolyte, which is specifically completed by the following steps:

[0024] 1. Weighing a eutectic solvent, a lithium salt, water, a photocurable monomer, a photocurable crosslinker, and a photoinitiator to obtain a hydrated eutectic polymer electrolyte composition;

[0025] The eutectic solvent in step 1 is one or more of acetamide, N-methylacetamide, urea, methylurea, tetramethylurea, trifluoroacetamide, N-methyltrifluoroacetamide, 1,2-dimethylimidazole and sulfolane;

[0026] The lithium salt described in step 1 is one or more of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorooxalatoborate), lithium trifluoromethanesulfonate, lithium tetrafluoroborate, lithium perchlorate, lithium nitrate and lithium chloride;

[0027] 2. Under light-proof conditions, mix the eutectic solvent, lithium salt, water, photocurable monomer, photocurable crosslinker and photoinitiator weighed in step 1, stir evenly, and let it stand for a period of time to obtain an unpolymerized electrolyte precursor; pour the unpolymerized electrolyte precursor into a silicone mold, and then cure it under ultraviolet light for a period of time to obtain a hydrated eutectic polymer electrolyte.

[0028] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the eutectic solvent in step 1 accounts for 20% to 40% by mass of the hydrated eutectic polymer electrolyte composition, the lithium salt accounts for 25% to 45% by mass of the hydrated eutectic polymer electrolyte composition, the water accounts for 2% to 10% by mass of the hydrated eutectic polymer electrolyte composition, and the photocurable monomer accounts for 25% to 55% by mass of the hydrated eutectic polymer electrolyte composition. Other steps are the same as those in specific embodiment 1.

[0029] Specific embodiment 3: This embodiment differs from specific embodiments 1 or 2 in that: in step 1, the molar ratio of the lithium salt to the eutectic solvent is 1:(1-6); the molar ratio of the lithium salt to water is 1:(1-4); the mass fraction of the photocurable crosslinker in step 1 is 0% to 5% of the photocurable monomer; and the mass fraction of the photoinitiator in step 1 is 0.5% to 2% of the photocurable monomer. Other steps are the same as those in specific embodiments 1 or 2.

[0030] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that: the photocurable monomer described in step 1 is composed of a hydrogen bond-rich photocurable monomer and other photocurable monomers; the mass ratio of the hydrogen bond-rich photocurable monomer to the other photocurable monomer is (1 to 10):(1 to 10); the hydrogen bond-rich photocurable monomer is one or more of acrylamide, methacrylamide, N-methylacrylamide, N-methylmethylacrylamide, N-isopropylacrylamide, N-(butoxymethyl)acrylamide, 2-[[(butylamino)carbonyl]oxy]ethyl acrylate, diacetoneacrylamide, N-cyanomethylacrylamide, N-hydroxymethylacrylamide and hydroxyethyl (meth)acrylate; the other photocurable monomer is one or more of acryloylmorpholine, N,N-dimethylacrylamide, N,N-diethylacrylamide, methacrylate, 1-vinylimidazole, 2-methoxyethyl acrylate, methoxypolyethylene glycol acrylate, trifluoroethyl (meth)acrylate and hexafluorobutyl (meth)acrylate. The other steps are the same as those in the first to third embodiments.

[0031] Specific Embodiment 5: This embodiment differs from Specific Embodiments 1 to 4 in that the photocurable crosslinking agent in step 1 is one or more of N,N'-methylenebisacrylamide, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, tripropylene glycol diacrylate, ethoxylated trimethylolpropane triacrylate, and pentaerythritol tetraacrylate. The other steps are the same as Specific Embodiments 1 to 4.

[0032] Specific embodiment 6: This embodiment differs from specific embodiments 1 to 5 in that the photoinitiator in step 1 is one or more of ethyl 2,4,6-trimethylbenzoylphenylphosphonate, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 2-hydroxy-2-methylpropiophenone, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone, and benzophenone. The other steps are the same as specific embodiments 1 to 5.

[0033] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that the resting time in step 2 is 0.5 to 2 hours and the curing time in step 2 is 10 to 30 minutes. The other steps are the same as those in specific embodiments 1 to 6.

[0034] Specific embodiment eight: This embodiment is an application of a hydrated eutectic polymer electrolyte in the preparation of a solid-state electrochromic device.

[0035] Specific embodiment 9: This embodiment differs from specific embodiments 1 to 8 in that the method for preparing the solid-state electrochromic device is specifically completed according to the following steps:

[0036] 1. Laminating the working electrode layer and the counter electrode layer, separating any three sides of the laminate with adhesive strips, and then sealing. The distance between the working electrode and the counter electrode is the thickness of the electrolyte layer to obtain a laminated part;

[0037] The thickness of the electrolyte layer described in step 1 is 0.05 mm to 0.20 mm;

[0038] The working electrode layer in step 1 is one or a combination of tungsten oxide, molybdenum oxide, niobium oxide and vanadium oxide, and has a thickness of 100 nm to 1000 nm;

[0039] The counter electrode layer in step 1 is one or a combination of nickel oxide, Prussian blue, titanium oxide doped cerium oxide and manganese oxide, and has a thickness of 100 nm to 1000 nm;

[0040] 2. Injecting unpolymerized electrolyte precursor from the unsealed side of the laminate, and after the unpolymerized electrolyte precursor fills the gap between the working electrode layer and the counter electrode layer, sealing the unsealed side with a sealant to obtain a sealed laminate;

[0041] 3. curing the sealed laminate under ultraviolet light for a period of time to obtain a solid-state electrochromic device based on a hydrated eutectic polymer electrolyte;

[0042] The curing time in step 3 is 10 to 30 minutes. The other steps are the same as those in specific embodiments 1 to 8.

[0043] Specific embodiment 10: This embodiment differs from specific embodiments 1 to 9 in that: the solid-state electrochromic device based on the solid-state electrochromic device can be prepared into a flexible or rigid device by selecting a transparent substrate; the transparent substrate is a flexible substrate or a rigid substrate; the flexible substrate is polyethylene terephthalate, polyimide or polydimethylsiloxane; the rigid substrate is soda-lime glass, quartz glass or polycarbonate plate;

[0044] The current collector in the solid-state electrochromic device based on the solid-state electrochromic device is composed of a substrate and a transparent conductive layer; it is a transparent conductive electrode, and its transparent conductive layer is one or a combination of indium-doped tin oxide, fluorine-doped tin oxide, aluminum-doped zinc oxide and a metal grid; the thickness of the transparent conductive electrode is 50nm to 500nm;

[0045] The solid-state electrochromic device based on the solid-state electrochromic device can be prepared into a patterned device through template assistance, 3D printing or screen printing. The other steps are the same as those of the specific embodiments 1 to 9.

[0046] The following examples are used to verify the beneficial effects of the present invention:

[0047] Example 1: A method for preparing a hydrated eutectic polymer electrolyte, specifically comprising the following steps:

[0048] 1. Weigh 0.62 g of eutectic solvent, 0.61 g of lithium salt, 0.07 g of water, 0.71 g of photocurable monomer, and 0.01 g of photoinitiator to obtain a hydrated eutectic polymer electrolyte composition;

[0049] The eutectic solvent in step 1 is N-methylacetamide;

[0050] The lithium salt described in step 1 is lithium bis(trifluoromethylsulfonyl)imide;

[0051] The photocurable monomer in step 1 is composed of a hydrogen bond-rich photocurable monomer and other photocurable monomers; wherein the mass ratio of the hydrogen bond-rich photocurable monomer to the other photocurable monomer is 0.41:0.3;

[0052] The hydrogen bond-rich photocurable monomer is methacrylamide;

[0053] The other photocurable monomer is acryloylmorpholine;

[0054] The photoinitiator described in step 1 is ethyl 2,4,6-trimethylbenzoylphenylphosphonate;

[0055] 2. In a dark environment, mix the eutectic solvent, lithium salt, water, photocurable monomer, photocurable crosslinker and photoinitiator weighed in step 1, stir evenly, and let stand for 30 minutes to obtain an electrolyte precursor;

[0056] 3. Preparation of working electrode layer and counter electrode layer:

[0057] The WO3 layer as the working electrode layer was prepared on the ITO glass by electron beam evaporation method, with a thickness of about 350nm; the NiO x The layer serves as the counter electrode layer, and has a thickness of approximately 450 nm;

[0058] 4. Preparation of solid-state electrochromic devices:

[0059] ①. Stack the working electrode layer and the counter electrode layer, then separate any three sides of the stack with 0.1mm tape and seal. The distance between the working electrode and the counter electrode is the thickness of the electrolyte layer to obtain a stacked piece.

[0060] ② Injecting unpolymerized electrolyte precursor from the unsealed side of the laminate, and after the unpolymerized electrolyte precursor fills the gap between the working electrode layer and the counter electrode layer, use a sealant to seal the unsealed side to obtain a sealed laminate;

[0061] ③. The sealed laminate is placed under ultraviolet light for curing for 20 minutes to obtain a solid-state electrochromic device based on a solid-state electrochromic device.

[0062] Example 2: A method for preparing a hydrated eutectic polymer electrolyte is specifically completed by the following steps:

[0063] 1. Weigh 0.56 g of eutectic solvent, 0.57 g of lithium salt, 0.16 g of water, 0.71 g of photocurable monomer, and 0.01 g of photoinitiator to obtain a hydrated eutectic polymer electrolyte composition;

[0064] The eutectic solvent in step 1 is N-methylacetamide;

[0065] The lithium salt described in step 1 is lithium bis(trifluoromethylsulfonyl)imide;

[0066] The photocurable monomer in step 1 is composed of a hydrogen bond-rich photocurable monomer and other photocurable monomers; wherein the mass ratio of the hydrogen bond-rich photocurable monomer to the other photocurable monomer is 0.41:0.3;

[0067] The hydrogen bond-rich photocurable monomer is methacrylamide;

[0068] The other photocurable monomer is acryloylmorpholine;

[0069] The photoinitiator described in step 1 is ethyl 2,4,6-trimethylbenzoylphenylphosphonate;

[0070] 2. In a dark environment, mix the eutectic solvent, lithium salt, water, photocurable monomer, photocurable crosslinker and photoinitiator weighed in step 1, stir evenly, and let stand for 30 minutes to obtain an electrolyte precursor;

[0071] 3. Preparation of working electrode layer and counter electrode layer:

[0072] The WO3 layer as the working electrode layer was prepared on the ITO glass by electron beam evaporation method, with a thickness of about 350nm; the NiO x The layer serves as the counter electrode layer, and has a thickness of approximately 450 nm;

[0073] 4. Preparation of solid-state electrochromic devices:

[0074] ①. Stack the working electrode layer and the counter electrode layer, then separate any three sides of the stack with 0.1mm tape and seal. The distance between the working electrode and the counter electrode is the thickness of the electrolyte layer to obtain a stacked piece.

[0075] ② Injecting unpolymerized electrolyte precursor from the unsealed side of the laminate, and after the unpolymerized electrolyte precursor fills the gap between the working electrode layer and the counter electrode layer, use a sealant to seal the unsealed side to obtain a sealed laminate;

[0076] ③. The sealed laminate is placed under ultraviolet light for curing for 20 minutes to obtain a solid-state electrochromic device based on a solid-state electrochromic device.

[0077] Example 3: A method for preparing a hydrated eutectic polymer electrolyte is specifically completed by the following steps:

[0078] 1. Weigh 0.48 g of eutectic solvent, 0.76 g of lithium salt, 0.06 g of water, 0.71 g of photocurable monomer, 0.01 g of photocurable crosslinker and 0.01 g of photoinitiator to obtain a hydrated eutectic polymer electrolyte composition;

[0079] The eutectic solvent in step 1 is trifluoroacetamide;

[0080] The lithium salt described in step 1 is lithium bis(trifluoromethylsulfonyl)imide;

[0081] The photocurable monomer in step 1 is composed of a hydrogen bond-rich photocurable monomer and other photocurable monomers; wherein the mass ratio of the hydrogen bond-rich photocurable monomer to the other photocurable monomer is 0.33:0.38;

[0082] The hydrogen bond-rich photocurable monomer is methacrylamide;

[0083] The other photocurable monomer is acryloylmorpholine;

[0084] The photocurable crosslinking agent in step 1 is polyethylene glycol diacrylate;

[0085] The photoinitiator described in step 1 is ethyl 2,4,6-trimethylbenzoylphenylphosphonate;

[0086] 2. In a dark environment, mix the eutectic solvent, lithium salt, water, photocurable monomer, photocurable crosslinker and photoinitiator weighed in step 1, stir evenly, and let stand for 30 minutes to obtain an electrolyte precursor;

[0087] 3. Preparation of working electrode layer and counter electrode layer:

[0088] The WO3 layer as the working electrode layer was prepared on the ITO glass by electron beam evaporation method, with a thickness of about 350nm; the NiO x The layer serves as the counter electrode layer, and has a thickness of approximately 450 nm;

[0089] 4. Preparation of solid-state electrochromic devices:

[0090] ①. Stack the working electrode layer and the counter electrode layer, then separate any three sides of the stack with 0.1mm tape and seal. The distance between the working electrode and the counter electrode is the thickness of the electrolyte layer to obtain a stacked piece.

[0091] ② Injecting unpolymerized electrolyte precursor from the unsealed side of the laminate, and after the unpolymerized electrolyte precursor fills the gap between the working electrode layer and the counter electrode layer, use a sealant to seal the unsealed side to obtain a sealed laminate;

[0092] ③. The sealed laminate is placed under ultraviolet light for curing for 20 minutes to obtain a solid-state electrochromic device based on a solid-state electrochromic device.

[0093] Example 4: A method for preparing a hydrated eutectic polymer electrolyte is specifically completed by the following steps:

[0094] 1. Weigh 0.44 g of eutectic solvent, 0.78 g of lithium salt, 0.08 g of water, 0.71 g of photocurable monomer, 0.01 g of photocurable crosslinker and 0.01 g of photoinitiator to obtain a hydrated eutectic polymer electrolyte composition;

[0095] The eutectic solvent in step 1 is N-methyltrifluoroacetamide;

[0096] The lithium salt described in step 1 is lithium bis(trifluoromethylsulfonyl)imide and lithium difluorooxalatoborate, wherein the mass ratio of lithium bis(trifluoromethylsulfonyl)imide to lithium difluorooxalatoborate is 0.72:0.06;

[0097] The photocurable monomer in step 1 is composed of a hydrogen bond-rich photocurable monomer and other photocurable monomers; wherein the mass ratio of the hydrogen bond-rich photocurable monomer to the other photocurable monomer is 0.33:0.38;

[0098] The hydrogen bond-rich photocurable monomer is methacrylamide;

[0099] The other photocurable monomer is acryloylmorpholine;

[0100] The photocurable crosslinking agent in step 1 is polyethylene glycol diacrylate;

[0101] The photoinitiator described in step 1 is ethyl 2,4,6-trimethylbenzoylphenylphosphonate;

[0102] 2. In a dark environment, mix the eutectic solvent, lithium salt, water, photocurable monomer, photocurable crosslinker and photoinitiator weighed in step 1, stir evenly, and let stand for 30 minutes to obtain an electrolyte precursor;

[0103] 3. Preparation of working electrode layer and counter electrode layer:

[0104] The WO3 layer as the working electrode layer was prepared on the ITO glass by electron beam evaporation method, with a thickness of about 350nm; the NiO x The layer serves as the counter electrode layer, and has a thickness of approximately 450 nm;

[0105] 4. Preparation of solid-state electrochromic devices:

[0106] ①. Stack the working electrode layer and the counter electrode layer, then separate any three sides of the stack with 0.1mm tape and seal. The distance between the working electrode and the counter electrode is the thickness of the electrolyte layer to obtain a stacked piece.

[0107] ② Injecting unpolymerized electrolyte precursor from the unsealed side of the laminate, and after the unpolymerized electrolyte precursor fills the gap between the working electrode layer and the counter electrode layer, use a sealant to seal the unsealed side to obtain a sealed laminate;

[0108] ③. The sealed laminate is placed under ultraviolet light for curing for 20 minutes to obtain a solid-state electrochromic device based on a solid-state electrochromic device.

[0109] Example 5: A method for preparing a hydrated eutectic polymer electrolyte is specifically completed by the following steps:

[0110] 1. Weigh 0.5 g of eutectic solvent, 0.82 g of lithium salt, 0.08 g of water, 0.6 g of photocurable monomer, 5 mg of photocurable crosslinker and 0.01 g of photoinitiator to obtain a hydrated eutectic polymer electrolyte composition;

[0111] The eutectic solvent in step 1 is acetamide;

[0112] The lithium salt described in step 1 is lithium bis(trifluoromethylsulfonyl imide) and lithium bis(fluorosulfonyl imide), wherein the mass ratio of lithium bis(trifluoromethylsulfonyl imide) to lithium bis(fluorosulfonyl imide) is 0.72:0.1;

[0113] The photocurable monomer in step 1 is composed of a hydrogen bond-rich photocurable monomer and other photocurable monomers; wherein the mass ratio of the hydrogen bond-rich photocurable monomer to the other photocurable monomer is 0.42:0.18;

[0114] The hydrogen bond-rich photocurable monomer is methacrylamide;

[0115] The other photocurable monomer is trifluoroethyl methacrylate;

[0116] The photocurable crosslinking agent in step 1 is N,N'-methylenebisacrylamide;

[0117] The photoinitiator described in step 1 is ethyl 2,4,6-trimethylbenzoylphenylphosphonate;

[0118] 2. In a dark environment, mix the eutectic solvent, lithium salt, water, photocurable monomer, photocurable crosslinker and photoinitiator weighed in step 1, stir evenly, and let stand for 30 minutes to obtain an electrolyte precursor;

[0119] 3. Preparation of working electrode layer and counter electrode layer:

[0120] The WO3 layer as the working electrode layer was prepared on the ITO glass by electron beam evaporation method, with a thickness of about 350nm; the NiO x The layer serves as the counter electrode layer, and has a thickness of approximately 450 nm;

[0121] 4. Preparation of solid-state electrochromic devices:

[0122] ①. Stack the working electrode layer and the counter electrode layer, then separate any three sides of the stack with 0.1mm tape and seal. The distance between the working electrode and the counter electrode is the thickness of the electrolyte layer to obtain a stacked piece.

[0123] ② Injecting unpolymerized electrolyte precursor from the unsealed side of the laminate, and after the unpolymerized electrolyte precursor fills the gap between the working electrode layer and the counter electrode layer, use a sealant to seal the unsealed side to obtain a sealed laminate;

[0124] ③. The sealed laminate is placed under ultraviolet light for curing for 20 minutes to obtain a solid-state electrochromic device based on a solid-state electrochromic device.

[0125] Example 6: A method for preparing a hydrated eutectic polymer electrolyte is specifically completed by the following steps:

[0126] 1. Weigh 0.93 g of eutectic solvent, 0.26 g of lithium salt, 0.1 g of water, 0.6 g of photocurable monomer, 5 mg of photocurable crosslinker and 0.01 g of photoinitiator to obtain a hydrated eutectic polymer electrolyte composition;

[0127] The eutectic solvent in step 1 is N-methyltrifluoroacetamide;

[0128] The lithium salt described in step 1 is lithium difluorooxalatoborate;

[0129] The photocurable monomer in step 1 is composed of a hydrogen bond-rich photocurable monomer and other photocurable monomers; wherein the mass ratio of the hydrogen bond-rich photocurable monomer to the other photocurable monomer is 0.52:0.08;

[0130] The hydrogen bond-rich photocurable monomer is methacrylamide;

[0131] The other photocurable monomer is hexafluorobutyl methacrylate;

[0132] The photocurable crosslinking agent in step 1 is N,N'-methylenebisacrylamide;

[0133] The photoinitiator described in step 1 is ethyl 2,4,6-trimethylbenzoylphenylphosphonate;

[0134] II. The eutectic solvent, lithium salt, water, photocurable monomer, photocurable crosslinking agent and photoinitiator weighed in step I are mixed under light shielding condition, stirred uniformly, and then left to stand for 30 min to obtain an electrolyte precursor;

[0135] III. Preparation of working electrode layer and counter electrode layer:

[0136] The WO3 layer is prepared on ITO glass as the working electrode layer by electron beam evaporation method, with a thickness of about 350 nm; the NiO x layer is prepared on ITO glass as the counter electrode layer by electron beam evaporation method, with a thickness of about 450 nm;

[0137] IV. Preparation of solid-state electrochromic device:

[0138] ①. The working electrode layer and the counter electrode layer are laminated, and then any three edges of the laminated product are spaced by 0.1 mm adhesive tape, and then sealed, with the distance between the working electrode and the counter electrode being the thickness of the electrolyte layer, to obtain a laminated product;

[0139] ②. The un-polymerized electrolyte precursor is injected from the unsealed side of the laminated product, and then the unsealed side is sealed by using sealing glue after the un-polymerized electrolyte precursor fills the gap between the working electrode layer and the counter electrode layer, to obtain a sealed laminated product;

[0140] ③. The sealed laminated product is placed under ultraviolet light for curing for 20 min to obtain a solid-state electrochromic device based on a solid-state electrochromic device.

[0141] Example 7: A preparation method of a hydrated eutectic polymer electrolyte, which is completed according to the following steps:

[0142] I. 0.58 g of eutectic solvent, 0.72 g of lithium salt, 0.10 g of water, 0.6 g of photocurable monomer, 2 mg of photocurable crosslinking agent and 10 mg of photoinitiator are weighed to obtain a hydrated eutectic polymer electrolyte composition;

[0143] The eutectic solvent in step I is sulfolane;

[0144] The lithium salt in step I is lithium bis(trifluoromethylsulfonyl)imide;

[0145] The photocurable monomer in step I is composed of a hydrogen bond-rich photocurable monomer and other photocurable monomers; the mass ratio of the hydrogen bond-rich photocurable monomer to the other photocurable monomers is 0.52:0.08;

[0146] The hydrogen bond-rich photocurable monomer is methacrylamide;

[0147] The other photocurable monomer is hexafluorobutyl methacrylate;

[0148] The photocurable crosslinking agent in step 1 is N,N'-methylenebisacrylamide;

[0149] The photoinitiator described in step 1 is ethyl 2,4,6-trimethylbenzoylphenylphosphonate and 2-hydroxy-2-methylpropiophenone, wherein the mass ratio of ethyl 2,4,6-trimethylbenzoylphenylphosphonate to 2-hydroxy-2-methylpropiophenone is 1:1;

[0150] 2. In a dark environment, mix the eutectic solvent, lithium salt, water, photocurable monomer, photocurable crosslinker and photoinitiator weighed in step 1, stir evenly, and let stand for 30 minutes to obtain an electrolyte precursor;

[0151] 3. Preparation of working electrode layer and counter electrode layer:

[0152] The WO3 layer as the working electrode layer was prepared on the ITO glass by electron beam evaporation method, with a thickness of about 350nm; the NiO x The layer serves as the counter electrode layer, and has a thickness of approximately 450 nm;

[0153] 4. Preparation of solid-state electrochromic devices:

[0154] ①. Stack the working electrode layer and the counter electrode layer, then separate any three sides of the stack with 0.1mm tape and seal. The distance between the working electrode and the counter electrode is the thickness of the electrolyte layer to obtain a stacked piece.

[0155] ② Injecting unpolymerized electrolyte precursor from the unsealed side of the laminate, and after the unpolymerized electrolyte precursor fills the gap between the working electrode layer and the counter electrode layer, use a sealant to seal the unsealed side to obtain a sealed laminate;

[0156] ③. The sealed laminate is placed under ultraviolet light for curing for 20 minutes to obtain a solid-state electrochromic device based on a solid-state electrochromic device.

[0157] Example 8: A method for preparing a hydrated eutectic polymer electrolyte is specifically completed by the following steps:

[0158] 1. Weigh 0.58 g of eutectic solvent, 0.72 g of lithium salt, 0.10 g of water, 0.6 g of photocurable monomer, 2 mg of photocurable crosslinker, and 10 mg of photoinitiator to obtain a hydrated eutectic polymer electrolyte composition;

[0159] The eutectic solvent in step 1 is trifluoroacetamide and sulfolane, wherein the mass ratio of trifluoroacetamide to sulfolane is 0.4:0.18;

[0160] The lithium salt described in step 1 is lithium bis(trifluoromethylsulfonyl)imide;

[0161] The photocurable monomer in step 1 is composed of a hydrogen bond-rich photocurable monomer and other photocurable monomers; wherein the mass ratio of the hydrogen bond-rich photocurable monomer to the other photocurable monomer is 0.42:0.18;

[0162] The hydrogen bond-rich photocurable monomer is methacrylamide;

[0163] The other photocurable monomer is trifluoroethyl methacrylate;

[0164] The photocurable crosslinking agent in step 1 is N,N'-methylenebisacrylamide;

[0165] The photoinitiator described in step 1 is ethyl 2,4,6-trimethylbenzoylphenylphosphonate and 2-hydroxy-2-methylpropiophenone, wherein the mass ratio of ethyl 2,4,6-trimethylbenzoylphenylphosphonate to 2-hydroxy-2-methylpropiophenone is 1:1;

[0166] 2. In a dark environment, mix the eutectic solvent, lithium salt, water, photocurable monomer, photocurable crosslinker and photoinitiator weighed in step 1, stir evenly, and let stand for 30 minutes to obtain an electrolyte precursor;

[0167] 3. Preparation of working electrode layer and counter electrode layer:

[0168] The WO3 layer as the working electrode layer was prepared on the ITO glass by electron beam evaporation method, with a thickness of about 350nm; the NiO x The layer serves as the counter electrode layer, and has a thickness of approximately 450 nm;

[0169] 4. Preparation of solid-state electrochromic devices:

[0170] ①. Stack the working electrode layer and the counter electrode layer, then separate any three sides of the stack with 0.1mm tape and seal. The distance between the working electrode and the counter electrode is the thickness of the electrolyte layer to obtain a stacked piece.

[0171] ② Injecting unpolymerized electrolyte precursor from the unsealed side of the laminate, and after the unpolymerized electrolyte precursor fills the gap between the working electrode layer and the counter electrode layer, use a sealant to seal the unsealed side to obtain a sealed laminate;

[0172] ③. The sealed laminate is placed under ultraviolet light for curing for 20 minutes to obtain a solid-state electrochromic device based on a solid-state electrochromic device.

[0173] Example 9: This example differs from Example 4 in that the light-curing crosslinking agent in step 1 is pentaerythritol tetraacrylate. The other steps and parameters are the same as those in Example 4.

[0174] Example 10: This example differs from Example 1 in that an MnO2 layer with a thickness of approximately 300 nm is deposited on the ITO glass using electron beam evaporation as the counter electrode layer. The other steps and parameters are the same as those in Example 1.

[0175] Comparative Example 1: In this example, an electrolyte was prepared and used in a solid-state electrochromic device. The specific steps are as follows:

[0176] 1) Preparation of a hydrated eutectic-based polymer electrolyte precursor: Under light-shielding conditions, 0.66 g of lithium bis(trifluoromethylsulfonyl)imide, 0.64 g of N-methylacetamide, 0.41 g of methacrylamide, and 0.30 g of acryloylmorpholine were mixed and stirred uniformly, and then 0.01 g of photoinitiator 2,4,6-trimethylbenzoylphenylphosphonic acid ethyl ester was added and stirred uniformly again. The mixture was allowed to stand for more than 30 minutes until all bubbles were eliminated to obtain an electrolyte precursor;

[0177] 2) Preparation of electrochromic layer and counter electrode layer: WO3 layer was prepared on ITO glass by electron beam evaporation method with a thickness of about 350nm; NiO was also prepared on ITO glass by electron beam evaporation method. x The layer serves as the counter electrode layer, and has a thickness of approximately 450 nm;

[0178] 3) Preparation of a solid-state electrochromic device: The working electrode and the counter electrode are stacked, and any three sides are separated and sealed with 0.1 mm thick adhesive strips to obtain a stacked piece; an unpolymerized electrolyte precursor is injected into the unsealed side of the stacked piece. After the precursor fills the gap between the working electrode and the counter electrode, the unsealed side is sealed with a sealant. After in situ UV curing for 20 minutes, a solid-state electrochromic device is obtained.

[0179] Figure 1 These are digital photos of the large-scale solid-state electrochromic device based on the hydrated eutectic polymer electrolyte prepared in Example 1 in the colored state and the faded state;

[0180] from Figure 1 It is clear that the use of hydrated eutectic polymer electrolytes can produce large-scale solid-state electrochromic devices, which show great potential for application in the field of smart windows. Specifically, the device exhibits uniform color change in both the tinted and faded states: in the faded state, light is efficiently transmitted, ensuring good lighting performance; in the tinted state, it effectively blocks most sunlight.

[0181] Figure 21 is the transmittance curve of the solid-state electrochromic device based on the hydrated eutectic polymer electrolyte prepared in Example 1 in the colored state and the faded state;

[0182] from Figure 2 It can be seen that the solid-state electrochromic device prepared using hydrated eutectic polymer electrolyte has a very high optical contrast, can provide excellent visual effects, improve information display quality and energy saving effect.

[0183] Figure 3 This is a graph showing the response speed of the solid-state electrochromic device based on the hydrated eutectic polymer electrolyte prepared in Example 1 during the coloring and fading processes;

[0184] from Figure 3 It can be seen that solid-state electrochromic devices prepared using hydrated eutectic polymer electrolytes have very fast response speeds, can improve user experience, enhance safety, broaden application areas, and reduce energy consumption.

[0185] Figure 4 Transmittance curves of the solid-state electrochromic device prepared in Comparative Example 1 in the colored state and the faded state;

[0186] from Figure 4 It can be seen that the optical contrast of the solid-state electrochromic device prepared with pure eutectic polymer electrolyte is lower than that with hydrated eutectic polymer electrolyte, which further highlights the advantages of hydrated eutectic polymer electrolyte.

[0187] Figure 5 The transmittance curves of the solid-state electrochromic device prepared in Example 1 in the colored state and the faded state;

[0188] from Figure 5 It can be seen that the response speed of the solid-state electrochromic device prepared with pure eutectic polymer electrolyte is slower than that with hydrated eutectic polymer electrolyte, which also highlights the advantages of hydrated eutectic polymer electrolyte.

Claims

1. A method for preparing a hydrated eutectic polymer electrolyte, characterized in that The preparation method is specifically completed according to the following steps:

1. Weighing a eutectic solvent, a lithium salt, water, a photocurable monomer, a photocurable crosslinker, and a photoinitiator to obtain a hydrated eutectic polymer electrolyte composition; The eutectic solvent in step 1 is one or more of acetamide, N-methylacetamide, urea, methylurea, tetramethylurea, trifluoroacetamide, N-methyltrifluoroacetamide, 1,2-dimethylimidazole and sulfolane; The lithium salt described in step 1 is one or more of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorooxalatoborate), lithium trifluoromethanesulfonate, lithium tetrafluoroborate, lithium perchlorate, lithium nitrate and lithium chloride; 2. Under light-proof conditions, mix the eutectic solvent, lithium salt, water, photocurable monomer, photocurable crosslinker and photoinitiator weighed in step 1, stir evenly, and let it stand for a period of time to obtain an unpolymerized electrolyte precursor; pour the unpolymerized electrolyte precursor into a silicone mold, and then cure it under ultraviolet light for a period of time to obtain a hydrated eutectic polymer electrolyte.

2. The method for preparing a hydrated eutectic polymer electrolyte according to claim 1, characterized in that The eutectic solvent described in step one accounts for 20% to 40% by mass of the hydrated eutectic polymer electrolyte composition, the lithium salt accounts for 25% to 45% by mass of the hydrated eutectic polymer electrolyte composition, the water accounts for 2% to 10% by mass of the hydrated eutectic polymer electrolyte composition, and the photocurable monomer accounts for 25% to 55% by mass of the hydrated eutectic polymer electrolyte composition.

3. The method for preparing a hydrated eutectic polymer electrolyte according to claim 1, characterized in that The molar ratio of the lithium salt to the eutectic solvent in step one is 1:(1-6); the molar ratio of the lithium salt to water is 1:(1-4); the mass fraction of the photocurable crosslinker described in step one to the photocurable monomer is 0% to 5%; the mass fraction of the photoinitiator described in step one to the photocurable monomer is 0.5% to 2%.

4. The method for preparing a hydrated eutectic polymer electrolyte according to claim 1, characterized in that The photocurable monomers described in step 1 are composed of hydrogen bond-rich photocurable monomers and other photocurable monomers; wherein the mass ratio of the hydrogen bond-rich photocurable monomers to the other photocurable monomers is (1-10):(1-10); the hydrogen bond-rich photocurable monomers are one or more of acrylamide, methacrylamide, N-methylacrylamide, N-methylmethylacrylamide, N-isopropylacrylamide, N-(butoxymethyl)acrylamide, 2-[[(butylamino)carbonyl]oxy]ethyl acrylate, diacetoneacrylamide, N-cyanomethacrylamide, N-hydroxymethylacrylamide and hydroxyethyl (meth)acrylate; the other photocurable monomers are one or more of acryloylmorpholine, N,N-dimethylacrylamide, N,N-diethylacrylamide, methacrylate, 1-vinylimidazole, 2-methoxyethyl acrylate, methoxypolyethylene glycol acrylate, trifluoroethyl (meth)acrylate and hexafluorobutyl (meth)acrylate.

5. The method for preparing a hydrated eutectic polymer electrolyte according to claim 1, characterized in that The photocurable crosslinking agent in step 1 is one or more of N,N'-methylenebisacrylamide, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, tripropylene glycol diacrylate, ethoxylated trimethylolpropane triacrylate and pentaerythritol tetraacrylate.

6. The method for preparing a hydrated eutectic polymer electrolyte according to claim 1, characterized in that The photoinitiator described in step 1 is one or more of ethyl 2,4,6-trimethylbenzoylphenylphosphonate, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, 2-hydroxy-2-methylpropiophenone, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone and benzophenone.

7. The method for preparing a hydrated eutectic polymer electrolyte according to claim 1, characterized in that The standing time in step 2 is 0.5 h to 2 h; the curing time in step 2 is 10 min to 30 min.

8. Use of a hydrated eutectic polymer electrolyte prepared by the preparation method according to claim 1, characterized in that A hydrated eutectic polymer electrolyte is used in the preparation of solid-state electrochromic devices.

9. The use of a hydrated eutectic polymer electrolyte according to claim 8, characterized in that The method for preparing the solid-state electrochromic device is specifically completed according to the following steps:

1. Laminating the working electrode layer and the counter electrode layer, separating any three sides of the laminate with adhesive strips, and then sealing. The distance between the working electrode and the counter electrode is the thickness of the electrolyte layer to obtain a laminated part; The thickness of the electrolyte layer described in step 1 is 0.05 mm to 0.20 mm; The working electrode layer in step 1 is one or a combination of tungsten oxide, molybdenum oxide, niobium oxide and vanadium oxide, and has a thickness of 100 nm to 1000 nm; The counter electrode layer in step 1 is one or a combination of nickel oxide, Prussian blue, titanium oxide doped cerium oxide and manganese oxide, and has a thickness of 100 nm to 1000 nm; 2. Injecting unpolymerized electrolyte precursor from the unsealed side of the laminate, and after the unpolymerized electrolyte precursor fills the gap between the working electrode layer and the counter electrode layer, sealing the unsealed side with a sealant to obtain a sealed laminate; 3. curing the sealed laminate under ultraviolet light for a period of time to obtain a solid-state electrochromic device based on a hydrated eutectic polymer electrolyte; The curing time described in step 3 is 10 minutes to 30 minutes.

10. The use of a hydrated eutectic polymer electrolyte according to claim 9, characterized in that The solid-state electrochromic device based on the solid-state electrochromic device can be prepared into a flexible or rigid device by selecting a transparent substrate; the transparent substrate is a flexible substrate or a rigid substrate; the flexible substrate is polyethylene terephthalate, polyimide or polydimethylsiloxane; the rigid substrate is soda-lime glass, quartz glass or polycarbonate plate; The current collector in the solid-state electrochromic device based on the solid-state electrochromic device is composed of a substrate and a transparent conductive layer; it is a transparent conductive electrode, and its transparent conductive layer is one or a combination of indium-doped tin oxide, fluorine-doped tin oxide, aluminum-doped zinc oxide and a metal grid; the thickness of the transparent conductive electrode is 50nm to 500nm; The solid-state electrochromic device based on the solid-state electrochromic device can be prepared into a patterned device through template assistance, 3D printing or screen printing.

Images