CN115291450B - Method of printing electrolyte layer, electrochromic device and method of manufacturing the same - Google Patents

Abstract

The invention discloses a method for printing an electrolyte layer, an electrochromic device and a preparation method thereof, wherein the method for printing the electrolyte layer comprises the following steps: obtaining electrolyte slurry, and mixing the electrolyte slurry with a diluent to obtain electrolyte diluent with the viscosity of 4000-40000 mPa.s; printing the electrolyte thinner on the substrate by adopting a screen printing mode to form a printing layer on the substrate; removing the diluent in the printing layer to obtain a prefabricated layer; and curing the prefabricated layer to obtain the electrolyte layer. The method for printing the electrolyte layer can ensure that the viscosity of the electrolyte slurry meets the requirement of screen printing and can also keep the shape of the uncured electrolyte layer in the process of assembling the electrochromic device.

Description

Method for printing electrolyte layer, electrochromic device and preparation method thereof

Technical Field

The present invention relates to the field of printed electronic technology, in particular to a method for printing an electrolyte layer, an electrochromic device and a preparation method thereof.

Background technique

One challenge in the industrial application of electrochromic devices is the large-scale green process preparation, and one of the main problems is the printing preparation of large-area electrolytes. The traditional grouting and scraping methods cannot achieve very precise electrolyte layer preparation, and secondly, the flatness and uniformity of the electrolyte film layer cannot be reliably guaranteed. The use of screen printing to prepare the electrolyte layer can solve the above problems, but in the assembly process of electrochromic devices, when the viscosity of the electrolyte slurry formula is too small, the shape retention of the electrochromic device during assembly is poor; when the viscosity of the electrolyte slurry formula is too high, the slurry screen penetration is poor and the corresponding pattern cannot be printed.

The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

Summary of the invention

The object of the present invention is to provide a method for printing an electrolyte layer, which can not only make the viscosity of the electrolyte slurry meet the requirements of screen printing, but also can maintain the shape of the uncured electrolyte layer during the assembly process of the electrochromic device.

Another object of the present invention is to provide an electrochromic device and a method for preparing the same.

To achieve the above object, an embodiment of the present invention provides a method for printing an electrolyte layer, comprising the following steps:

Obtaining an electrolyte slurry, and mixing it with a diluent to obtain an electrolyte diluent having a viscosity of 4000-40000 mPa·s;

Printing the electrolyte diluent on the substrate by screen printing to form a printed layer on the substrate;

removing the diluent in the printed layer to obtain a prefabricated layer; and

The prefabricated layer is cured to obtain an electrolyte layer.

In one or more embodiments of the present invention, the viscosity of the prefabricated layer is greater than or equal to 80000 mPa·s.

In one or more embodiments of the present invention, the step of removing the diluent in the printing layer comprises:

The printed layer is heated to remove the diluent in the printed layer.

In one or more embodiments of the present invention, the curing process is a photocuring process or a thermal curing process.

In one or more embodiments of the present invention, the diluent includes at least one of ethyl acetate, ethanol and water.

In one or more embodiments of the present invention, the electrolyte slurry includes a polymer host, a plasticizer, a lithium salt, a photoinitiator, and a cross-linking agent.

In one or more embodiments of the present invention, the cross-linking agent is one of polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, and trimethylolpropane acrylate; and/or,

The polymer body includes at least one of polymethyl methacrylate, polyvinyl fluoride and polyurethane.

In one or more embodiments of the present invention, the lithium salt is at least one of lithium perchlorate and lithium bis(trifluoromethanesulfonyl)imide; and/or,

The plasticizer includes at least one of polycarbonate, dimethyl carbonate, ethylene carbonate and water.

An embodiment of the present invention further provides a method for preparing an electrochromic device, comprising the following steps:

Obtaining an electrolyte slurry, and mixing it with a diluent to obtain an electrolyte diluent having a viscosity of 4000-40000 mPa·s;

Printing the electrolyte diluent on the first electrode by screen printing to form a printed layer on the first electrode;

removing the diluent in the printed layer to obtain a prefabricated layer;

Laminating the prefabricated layer on the first electrode to the second electrode; and

The prefabricated layer is cured to obtain an electrochromic device.

An embodiment of the present invention provides an electrochromic device, which is manufactured using the above-mentioned method for manufacturing an electrochromic device.

Compared with the prior art, the method for printing an electrolyte layer according to an embodiment of the present invention mixes the electrolyte slurry with a diluent so that the viscosity of the electrolyte diluent meets the requirements of screen printing. After screen printing, the diluent in the printed layer is removed to increase the viscosity of the printed layer. The printed layer is in an uncured state, so that the printed layer has a certain rigidity and a certain wettability, can maintain its own shape to suppress the extension phenomenon during the bonding process, and can ensure that the uncured electrolyte layer can be in close contact with other functional layers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart of a method for printing an electrolyte layer according to one embodiment of the present invention;

FIG2 is a schematic diagram of an electrochromic device according to an embodiment of the present invention;

FIG3 is a schematic diagram of the electrochromic device in Example 1 in a faded transparent state;

FIG4 is a schematic diagram of the electrochromic device in Example 1 in a colored state;

FIG. 5 is a diagram showing a state in which the electrolyte slurry is printed on a substrate in an electrolyte layer printed by conventional screen printing.

Detailed ways

The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific implementation modes.

As shown in FIG. 1 , a method for printing an electrolyte layer according to a preferred embodiment of the present invention comprises the following steps:

S11, obtaining an electrolyte slurry, and mixing it with a diluent to obtain an electrolyte diluent having a viscosity of 4000-40000 mPa·s.

The electrolyte slurry may include a polymer body, a plasticizer, a lithium salt, a photoinitiator and a crosslinking agent. Specifically, the crosslinking agent is polyethylene glycol diacrylate. The polymer body may include at least one of polymethyl methacrylate and polyvinyl fluoride. The lithium salt is at least one of lithium perchlorate and lithium bistrifluoromethanesulfonyl imide. The plasticizer includes at least one of polycarbonate, dimethyl carbonate, ethylene carbonate and water. The viscosity of the electrolyte slurry may be greater than or equal to 80000 mPa·s.

Specifically, the diluent includes at least one of ethyl acetate, ethanol, and water. The role of the diluent is to dilute the electrolyte slurry so that the viscosity of the mixed electrolyte diluent is 4000-40000mPa·s. To meet the requirements of screen printing. The boiling point of the diluent is lower than the boiling point of the plasticizer. If the diluent is removed by heating in the later stage, it can be ensured that the diluent is removed as much as possible, while preventing or avoiding the reduction of the amount of plasticizer in the electrolyte slurry as much as possible.

It should be noted that the selection of diluent must meet the following conditions:

First, after removing the diluent at a later stage, the components in the prefabricated layer are made to be substantially the same as the components in the electrolyte slurry as much as possible. Substantially the same can be understood as the components and the corresponding contents being substantially the same.

Secondly, the diluent itself will not affect the working performance of the electrolyte slurry or the finally formed electrolyte layer to a certain extent.

S12, printing the electrolyte diluent on the substrate by screen printing to form a printed layer on the substrate.

S13, removing the diluent in the printing layer to obtain a prefabricated layer.

Specifically, the step of removing the diluent in the printing layer may include:

The printed layer is heated to remove the diluent in the printed layer. The heating temperature can be adjusted according to the selection of the diluent and the selection of the components in the electrolyte slurry. The heating temperature can be the boiling point of the diluent or about the boiling point of the diluent. In addition, the heating temperature is preferably such that other substances in the electrolyte slurry are prevented from volatilizing.

The viscosity of the prefabricated layer is greater than or equal to 80000 mPa·s, so that the prefabricated layer has a certain rigidity and can maintain its own shape to suppress the extension phenomenon during the bonding process.

It should be noted that the composition of the prefabricated layer and the composition of the electrolyte slurry can be considered to be basically the same or approximately the same.

S14, curing the prefabricated layer to obtain an electrolyte layer.

Specifically, the curing treatment is a photocuring treatment or a thermal curing treatment. For example, when the electrolyte slurry contains a photoinitiator and a polymer such as PEG-DA, the prefabricated layer can be cured by UV curing. When the electrolyte slurry contains other components such as maleimide, the prefabricated layer can be cured by thermal curing.

It should be noted that during the preparation process, the electrolyte layer has three states, namely, low viscosity, high viscosity and solid state. Among them, the low viscosity state corresponds to the state of the electrolyte diluent, which mainly meets the viscosity requirements of screen printing. The high viscosity state corresponds to the state of the prefabricated layer, which suppresses the extension phenomenon during the bonding process and provides a certain rigidity for the prefabricated layer. The high viscosity state can be understood as an incompletely solidified state, which has a certain wettability to ensure that the prefabricated layer can be in close contact with other functional layers. The solid state is the final state of the electrolyte layer, which serves to connect different substrates (or laminates).

An embodiment of the present invention provides an electrochromic device. In a specific implementation, the electrochromic device may include a first transparent electrode, a first electrode, an electrolyte layer, a second electrode, and a second transparent electrode stacked in sequence.

The first electrode can be considered as a counter electrode or an ion storage layer. The second electrode can be considered as a working electrode. The materials of the first transparent electrode and the second transparent electrode can be selected from ITO, IZO or Ag grid, etc. The material of the first electrode can be a functional material that can undergo electrochromic reaction, such as thiophene and its variants. The material of the second electrode can be a slurry of thiophene and its derivatives, _TiO2 , MCCP, etc.

In a specific embodiment, the present invention further provides a method for preparing the above electrochromic device, comprising the following steps:

S21. Obtain electrolyte slurry, and mix it with a diluent to obtain an electrolyte diluent having a viscosity of 4000-40000 mPa·s.

The electrolyte slurry may include a polymer body, a plasticizer, a lithium salt, a photoinitiator and a crosslinking agent. Specifically, the crosslinking agent is polyethylene glycol diacrylate. The polymer body may include at least one of polymethyl methacrylate and polyvinyl fluoride. The lithium salt is at least one of lithium perchlorate and lithium bistrifluoromethanesulfonyl imide. The plasticizer includes at least one of polycarbonate, dimethyl carbonate, ethylene carbonate and water. The viscosity of the electrolyte slurry may be greater than or equal to 80000 mPa·s. The photoinitiator may be 2,2-dimethoxy-2-phenylacetophenone.

Specifically, the diluent includes at least one of ethyl acetate, ethanol and water. The diluent dilutes the electrolyte slurry so that the viscosity of the mixed electrolyte dilution material is 4000-40000 mPa·s to meet the requirements of screen printing.

It should be noted that the selection of diluent must meet the following conditions:

First, after removing the diluent at a later stage, the components in the prefabricated layer are made to be substantially the same as the components in the electrolyte slurry as much as possible. Substantially the same can be understood as the components and the corresponding contents being substantially the same.

Secondly, the diluent itself will not affect the working performance of the electrolyte slurry or the finally formed electrolyte layer to a certain extent.

S22, printing the electrolyte diluent on the first electrode by screen printing to form a printed layer on the first electrode.

S23, removing the diluent in the printing layer to obtain a prefabricated layer.

Specifically, the step of removing the diluent in the printing layer may include:

The printed layer is heated to remove the diluent in the printed layer, wherein the heating temperature can be adjusted according to the selection of the diluent and the selection of the components in the electrolyte slurry.

The viscosity of the prefabricated layer is greater than or equal to 80000 mPa·s, so that the prefabricated layer has a certain rigidity and can maintain its own shape to suppress the extension phenomenon during the bonding process.

It should be noted that the composition of the prefabricated layer and the composition of the electrolyte slurry can be considered to be basically the same or approximately the same.

S24, bonding the prefabricated layer on the first electrode to the second electrode.

In step S24, the prefabricated layer on the first electrode is bonded to the second electrode to form a semi-finished product. During the bonding process, since the viscosity of the prefabricated layer is relatively high, i.e., greater than or equal to 80,000 mPa·s, the prefabricated layer has a certain rigidity and can maintain its own shape to suppress the extrusion force generated by the first electrode and the second electrode during the bonding process, thereby avoiding the stretching of the prefabricated layer.

It should be noted that the first electrode can be considered as the counter electrode or ion storage layer in the electrochromic device, and its formation method can be printing. The second electrode can be considered as the working electrode, and its formation method can be inkjet printing/spin coating/screen printing and the like.

S25, curing the prefabricated layer to obtain an electrochromic device.

Specifically, the curing treatment is a photocuring treatment or a thermal curing treatment. For example, when the electrolyte slurry contains a photoinitiator and a polymer such as PEG-DA, the prefabricated layer can be cured by UV curing. When the electrolyte slurry contains other components such as maleimide, the prefabricated layer can be cured by thermal curing.

The main electrochromic area of the electrochromic device prepared by the present invention can be greater than or equal to 10 cm*10 cm. The pixel size of the electrochromic device prepared based on the design method can reach 0.5 mm*0.5 mm. The electrochromic device based on the process can also print large-area 10 cm*10 cm (electrochromic area) devices. Maximum wavelength transmittance difference: 30-40%; at -0.6V, 0.8V driving voltage, fading and coloring response transmittance (change to 90% of the maximum transmittance difference) fading and coloring response time: both ~0.5s; coloring and fading state maintenance time>5h.

As shown in FIG2 , in a specific embodiment, the electrochromic device of ITO/PEDOT/electrolyte/PProDOT/ITO obtained by the preparation method of the present invention (i.e., the darker colored part in FIG2 ) can have an area size ranging from 1.5 mm*1.5 mm to 10 cm*10 cm. 550 nm is the maximum light modulation wavelength, and the maximum wavelength transmittance difference is 30-40%; at a driving voltage of -0.6 V and 0.8 V, the response time of fading and coloring is ～0.5 s; the coloring and fading state maintenance time is >5 h. The thickness of the electrolyte layer is 50 μm, and the electrolyte formula is PMMA/PC/PEGDA/water/LiTFSi/2,2-dimethoxy-2-phenylacetophenone.

In another specific embodiment, only a part of the electrochromic region may be an electrochromic region in the electrochromic device prepared by the preparation method of the present invention. In this case, the electrochromic region may be in a pattern (such as an animal shape, a smiley face, a graphic (triangle, square, etc.) or other graphic). The pattern is formed by screen printing the electrolyte layer only at the position where the color needs to be changed. Since screen printing is used, the pattern can be composed of several dots, that is, the electrolyte layer can be considered to be formed by several spaced dots.

In other embodiments, the patterned electrochromic region may also be a layered electrolyte layer (not a dotted layer) formed after the electrolyte slurry is cured, and the electrolyte layer is a flat film that can be observed by the naked eye, without obvious residual mesh marks or other problems.

As shown in Figure 5, Figure 5 is a picture of the electrolyte layer printed by the existing screen printing method. Since no diluent is added between the printed electrolyte layers, the viscosity of the electrolyte slurry is relatively low, which reduces the problem of mesh marks and wire drawing when printed on the substrate.

In addition, when the electrolyte layer is printed by the existing screen printing method, the viscosity of the electrolyte layer before curing is not adjusted after printing, resulting in insufficient rigidity of the uncured electrolyte layer when it is bonded to other devices. The desired pattern may not be maintained, resulting in deformation of the pattern formed by the electrochromic region of the electrochromic device finally obtained, resulting in a defective product.

The method for printing an electrolyte layer, the electrochromic device and the preparation method thereof of the present invention are described in detail below in conjunction with specific embodiments.

Example 1

The ITO material is screen printed to form a first transparent electrode, and PEDOT is screen printed to form a first electrode on the first transparent electrode. The ITO material is screen printed to form a second transparent electrode, and PProDOT is spin coated to form a second electrode on the second transparent electrode.

Weigh 3g of PMMA (polymethyl methacrylate), 5g of PC (polycarbonate), 5g of PEG-DA (polyethylene glycol diacrylate), 2.8g of LiTFSi and 15mg of 2,2-dimethoxy-2-phenylacetophenone respectively, stir evenly to obtain an electrolyte slurry with a viscosity of 88000mPa·s. Weigh 0.8g of water and 3g of ethyl acetate and mix with the electrolyte slurry to obtain an electrolyte diluent with a viscosity of 4000mPa·s.

The electrolyte diluent is printed on the first electrode by screen printing to obtain a printed layer, and the printed layer is heated at 60° C. for 5 minutes to obtain a prefabricated layer.

The second electrode was laminated to the prefabricated layer and cured under UV conditions to obtain the electrochromic device shown in FIG. 3 and FIG. 4 , wherein the thickness of the electrolyte layer was 50 μm.

Among them, Figure 3 is a schematic diagram of the electrochromic device in Example 1 in a faded transparent state, and Figure 4 is a schematic diagram of the electrochromic device in Example 1 in a colored state. It can be seen from Figures 3 and 4 that the color-changing pattern in the electrochromic device in Example 1 is a smiley face shape, and the shape of the dielectric layer in the electrochromic device is a smiley face composed of dots, so that the color-changing pattern in the electrochromic device is a smiley face shape.

Example 2

The ITO material is screen printed to form a first transparent electrode, and PEDOT is screen printed to form a first electrode on the first transparent electrode. In addition, a silver paste material is screen printed to form a second transparent electrode, and PProDOT is spin coated to form a second electrode on the second transparent electrode.

Weigh 4g of PMMA, 3g of EC (ethylene carbonate), 5g of PEG-DA, 2.8g of LiTFSi and 15mg of 2,2-dimethoxy-2-phenylacetophenone respectively, stir evenly to obtain an electrolyte slurry with a viscosity of 90000mPa·s. Weigh 0.8g of water and 4.5g of ethyl acetate and mix with the electrolyte slurry to obtain an electrolyte diluent with a viscosity of 4000mPa·s.

The electrolyte diluent is printed on the first electrode by screen printing to obtain a printed layer, and the printed layer is heated at 60° C. for 5 minutes to obtain a prefabricated layer.

The second electrode is laminated to the prefabricated layer and cured under UV conditions to obtain an electrochromic device, wherein the thickness of the electrolyte layer is 45 μm. The performance of the electrochromic device obtained in this embodiment is substantially the same as that of the electrochromic device obtained in Example 1.

Example 3

The ITO material is screen printed to form a first transparent electrode, and PEDOT is screen printed to form a first electrode on the first transparent electrode. The ITO material is screen printed to form a second transparent electrode, and PProDOT is spin coated to form a second electrode on the second transparent electrode.

Weigh 3g of PVDF (polyvinylidene fluoride), 5g of DEC (diethyl carbonate), 5g of PEG-DA, 2.8g of lithium perchlorate and 15mg of 2,2-dimethoxy-2-phenylacetophenone respectively, stir evenly to obtain an electrolyte slurry with a viscosity of 70000mPa·s. Weigh 0.8g of water and 3g of ethyl acetate and mix with the electrolyte slurry to obtain an electrolyte diluent with a viscosity of 4000mPa·s.

The electrolyte diluent is printed on the first electrode by screen printing to obtain a printed layer, and the printed layer is heated at 60° C. for 5 minutes to obtain a prefabricated layer.

The second electrode is laminated to the prefabricated layer and cured under UV conditions to obtain an electrochromic device, wherein the thickness of the electrolyte layer is 40 μm.

The performance of the electrochromic device obtained in this example is substantially the same as that of the electrochromic device obtained in Example 1.

In summary, the beneficial effects of the method for preparing the electrochromic device of the present invention are:

(1) The electrolyte slurry can meet the viscosity requirements of screen printing by using a diluent. The diluent is removed in a subsequent step to increase the viscosity of the electrolyte layer before curing, so that the electrolyte layer has a certain rigidity before curing and can maintain its own shape to suppress the extension phenomenon during the bonding process.

(2) Achieve the effect of stable and efficient large-area printing of electrolyte layers with uniform film thickness, good repeatability, and very thin film thickness, which can further improve the performance of electrochromic devices.

(3) By adding diluent, the thickness of the printed electrolyte layer can be effectively adjusted.

(4) The electrochromic device structure of the present invention has the advantages of rapid response and cyclic stability.

The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims (7)

1. A method for preparing an electrochromic device, characterized in that it comprises the following steps: Obtaining an electrolyte slurry, and mixing it with a diluent to obtain an electrolyte diluent having a viscosity of 4000-40000 mPa·s; Printing the electrolyte diluent on the first electrode by screen printing to form a printed layer on the first electrode; removing the diluent in the printed layer to obtain a prefabricated layer; Laminating the prefabricated layer on the first electrode to the second electrode; and curing the prefabricated layer to obtain an electrochromic device; Wherein, the diluent includes at least one of ethyl acetate, ethanol and water; the electrolyte slurry includes a polymer body, a plasticizer, a lithium salt, a photoinitiator and a cross-linking agent, wherein the boiling point of the diluent is lower than the boiling point of the plasticizer; and the prefabricated layer has rigidity and wettability. 2. The method for preparing an electrochromic device according to claim 1, wherein the viscosity of the prefabricated layer is greater than or equal to 80,000 mPa·s. 3. The method for preparing an electrochromic device according to claim 1, wherein the step of removing the diluent in the printed layer comprises: The printed layer is heated to remove the diluent in the printed layer. 4 . The method for preparing an electrochromic device according to claim 1 , wherein the curing treatment is a photocuring treatment or a thermal curing treatment. 5. The method for preparing an electrochromic device according to claim 1, characterized in that the crosslinking agent is one of polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, and trimethylolpropane acrylate; and/or, The polymer body includes at least one of polymethyl methacrylate, polyvinyl fluoride and polyurethane. 6. The method for preparing an electrochromic device according to claim 1, wherein the lithium salt is at least one of lithium perchlorate and lithium bis(trifluoromethanesulfonyl)imide; and/or, The plasticizer includes at least one of polycarbonate, dimethyl carbonate, diethyl carbonate, ethylene carbonate and water. 7. An electrochromic device, characterized in that it is made by the preparation method of the electrochromic device according to claim 1.