All-solid-state electrochromic device based on phosphate electrolyte and preparation method of all-solid-state electrochromic device

Abstract

The invention provides an all-solid-state electrochromic device based on phosphate electrolyte and a preparation method of the all-solid-state electrochromic device. The all-solid-state electrochromic device comprises a substrate, and a transparent conductive layer, an electrochromic layer, a phosphate electrolyte composite layer, an ion storage layer and an electron blocking layer which are sequentially stacked on the substrate, the phosphate electrolyte composite layer includes a first phosphate electrolyte layer and a second phosphate electrolyte layer. According to the electrochromic device provided by the invention, through the design of the composite phosphate electrolyte layer, the conductivity and stability of the device are improved, high ionic conductivity, response speed and long cycle life are realized, and meanwhile, through the electron barrier layer, reverse migration of electrons and ions is inhibited, and long-time color storage is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrochromic technology, and particularly relates to a full-solid-state electrochromic device based on a phosphate electrolyte and a preparation method thereof. BACKGROUND

[0002] Electrochromic technology is a technology that realizes color change by adjusting the optical properties of materials through an external electric field. In recent years, it has attracted widespread attention in the fields of smart windows, optical storage, display devices, and electronic ink. The core of electrochromic devices is to make electrochromic materials undergo redox reactions through an external electric field, thereby causing reversible changes in the optical properties of the materials, such as color, transparency, etc.

[0003] Currently, electrochromic devices are mainly divided into two types: liquid and full-solid-state. Liquid electrochromic devices have good ion conductivity and fast response speed, but they are prone to problems such as electrolyte leakage, volatilization, and decomposition during long-term use, leading to degradation of device performance. In contrast, full-solid-state electrochromic devices, with the high stability and sealing of solid-state electrolytes, avoid the leakage problem of liquid electrolytes and have a longer service life. However, existing full-solid-state electrochromic devices still face technical bottlenecks such as low ion conductivity, poor stability, and limited cycle life, especially in terms of response speed and high-performance storage.

[0004] Phosphate-type full-solid-state electrochromic devices are a relatively new type of electrochromic device. Phosphate materials have high ion conductivity, which can improve the response speed of electrochromic devices compared to traditional inorganic oxide films. In addition, phosphate materials have good chemical stability and are less prone to stress and cracking during electrochemical cycling, thereby extending the service life of the device and providing superior durability. At the same time, the low electrochemical window and high ion migration energy barrier of phosphate electrolytes help to reduce energy consumption and achieve low power consumption and long-term storage capacity. For example, CN112305828A discloses an inorganic full-solid-state electrochromic device and a preparation method thereof, which includes an ITO transparent conductive film layer, a WO3 electrochromic film, a phosphate proton conductor layer, a Nb-doped TiO2 ion storage layer, and an ITO transparent conductive film layer. It solves the problems of traditional liquid electrolytes, such as easy leakage, difficult packaging, and poor heat resistance of gel electrolytes, and has good electrochromic properties.

[0005] Despite the great potential of phosphate-type inorganic electrolytes in electrochromic devices, existing technologies still face some challenges. The ion conductivity of traditional phosphate electrolytes at room temperature is relatively low, usually less than 10 -4The low ionic conductivity of the electrolyte, typically in the range of 10-4-10-3S / cm, results in insufficient response speed of the device, and during high current density or long-term cycling, the electrolyte can undergo chemical degradation, affecting the stability and cycle life of the device. In addition, the high interfacial resistance between the electrolyte and the electrode limits the rapid migration of ions, affecting the energy efficiency and response speed of the device.

[0006] In this context, there is a need to develop a new type of all-solid-state electrochromic device aimed at improving ionic conductivity, stability, and addressing the issues of energy efficiency, storage capacity, and response speed of traditional devices. SUMMARY

[0007] The purpose of the present application is to provide an all-solid-state electrochromic device that improves the conductivity and stability of solid-state electrochromic devices.

[0008] To achieve this purpose, the present application uses the following technical solution:

[0009] In a first aspect, the present application provides an all-solid-state electrochromic device based on a phosphate electrolyte, comprising a substrate, and a transparent conductive layer, an electrochromic layer, a phosphate electrolyte composite layer, an ion storage layer, and an electron blocking layer stacked in order on the substrate.

[0010] The phosphate electrolyte composite layer comprises a first phosphate electrolyte layer and a second phosphate electrolyte layer.

[0011] The electrochromic device provided by the present application uses phosphate as the solid-state electrolyte layer, and uses a first phosphate electrolyte layer and a second phosphate electrolyte layer to form a composite electrolyte layer. The first phosphate electrolyte layer optimizes Na + The migration channel improves the ionic conductivity of the device, and the combination of the first phosphate electrolyte layer and the second phosphate electrolyte layer can fill the pinhole defects of the inner phosphate electrolyte layer, enhancing the environmental stability and mechanical strength of the electrolyte layer, thereby balancing and improving the conductivity and stability of the solid-state electrochromic device, achieving high ionic conductivity and long cycle life. In addition, the electron blocking layer is provided on the outer layer to inhibit the reverse migration of electrons and ions, prevent self-bleaching effect, and achieve long-term color storage.

[0012] Preferably, the thickness of the transparent conductive layer is 80-150 nm, for example, it can be 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm or 150 nm, but is not limited to the listed values, and other values not listed within the value range are also applicable.

[0013] Preferably, the transparent conductive layer comprises a transparent oxide layer on which a metal nanomesh layer is formed.

[0014] In the present application, the transparent conductive layer adopts a composite structure of metal nanometer grid and transparent oxide layer, the transparent oxide layer ensures the light transmittance of the conductive layer, the metal nanometer grid formed on the transparent oxide layer improves the conductivity of the conductive layer, at the same time, the grid structure guarantees the light transmittance of the conductive layer, and improves the mechanical flexibility and durability of the conductive layer, avoiding the risk of brittle fracture of single transparent oxide.

[0015] Preferably, the metal of the metal nanometer grid layer comprises silver and / or copper.

[0016] Preferably, the grid size of the metal nanometer grid layer is 5-10 μm, for example, can be 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0017] Preferably, the grid line diameter of the metal nanometer grid layer is 80-100 nm, for example, can be 80 nm, 85 nm, 90 nm, 95 nm or 100 nm, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0018] Preferably, the thickness of the metal nanometer grid layer is 50-80 nm, for example, can be 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm or 80 nm, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0019] Preferably, the material of the transparent oxide layer comprises ITO.

[0020] Preferably, the thickness of the transparent oxide layer is 30-70 nm, for example, can be 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm or 70 nm, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0021] Preferably, the material of the electrochromic layer comprises at least one of WO3, MoO3 or TiO2.

[0022] In the present application, the photosensitive material or pH sensitive material is used as the electrochromic layer material, so that the device can realize color regulation under the change of external light or pH environment, thereby widening the application scenarios of the device.

[0023] Preferably, the thickness of the electrochromic layer is 200-500 nm, for example, can be 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm or 500 nm, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0024] Preferably, the material of the first phosphate electrolyte layer comprises sodium metaphosphate.

[0025] Preferably, the thickness of the first phosphate electrolyte layer is 300-500 nm, for example, it can be 300 nm, 350 nm, 400 nm, 450 nm or 500 nm, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0026] Preferably, the material of the second phosphate electrolyte layer comprises AlPO4.

[0027] Preferably, the thickness of the second phosphate electrolyte layer is 50-100 nm, for example, it can be 50 nm, 60 nm, 70 nm, 80 nm, 90 nm or 100 nm, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0028] In the present application, through the combination of sodium metaphosphate and aluminum phosphate two layers of phosphate electrolyte, the electrolyte layer is simultaneously provided with high efficient Na + migration and environmental stability.

[0029] Preferably, the material of the ion storage layer comprises a metal oxide.

[0030] Preferably, the metal oxide comprises a nickel-based oxide and / or a vanadium-based oxide.

[0031] Preferably, the nickel-based oxide comprises NiO.

[0032] Preferably, the vanadium-based oxide comprises V2O5.

[0033] Preferably, the thickness of the ion storage layer is 100-300 nm, for example, it can be 100 nm, 150 nm, 200 nm, 250 nm or 300 nm, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0034] Preferably, the material of the electron blocking layer comprises ZrO2.

[0035] Preferably, the thickness of the electron blocking layer is 20-50 nm, for example, it can be 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm or 50 nm, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0036] Preferably, the all-solid-state electrochromic device further comprises: a two-dimensional material modification layer stacked between the electrochromic layer and the composite phosphate electrolyte layer.

[0037] In the present application, a two-dimensional material is introduced between the electrochromic layer and the electrolyte layer for interface modification, which can reduce the interface resistance, avoid interface side reactions, and improve the response speed and durability of the device.

[0038] Preferably, the material of the two-dimensional material modification layer comprises graphene and / or MoS2.

[0039] Preferably, the thickness of the two-dimensional material modification layer is 1-10 nm, for example, it can be 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm or 10 nm, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0040] Preferably, the all-solid-state electrochromic device further comprises a thermoelectric conversion layer stacked on the electron blocking layer.

[0041] In the present application, a temperature response functional layer is compounded on the composite layer structure, and the electrochromic reaction is driven by the thermoelectric conversion performance of the response layer using the change of environmental temperature, so as to realize self-powered color change without external voltage, and broaden the application of the device in passive scenarios.

[0042] Preferably, the thickness of the thermoelectric conversion layer is 5-20 μm, for example, it can be 5 μm, 10 μm, 15 μm or 20 μm, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0043] Preferably, the material of the thermoelectric conversion layer comprises Bi2Te3.

[0044] In a second aspect, the present application provides a preparation method of the all-solid-state electrochromic device based on phosphate electrolyte according to the first aspect, and the preparation method comprises: sequentially preparing a transparent conductive layer, an electrochromic layer, a first phosphate electrolyte layer, a second phosphate electrolyte layer, an ion storage layer and an electron blocking layer on a substrate.

[0045] Preferably, the preparation method of the transparent conductive layer comprises: first forming a grid pattern on the substrate by using nano-imprint lithography, forming a metal nanometer grid on the substrate by using electron beam evaporation deposition, then depositing a transparent oxide layer on the metal nanometer grid by using magnetron sputtering, and performing annealing treatment on the substrate with the deposited transparent conductive layer.

[0046] Preferably, the temperature of the annealing treatment is 240-260℃, for example, it can be 240℃, 245℃, 250℃, 255℃ or 260℃, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0047] Preferably, the electrochromic layer is prepared by using magnetron sputtering.

[0048] Preferably, the first phosphate electrolyte layer is prepared by radio frequency magnetron sputtering.

[0049] Preferably, the second phosphate electrolyte layer is prepared by atomic layer deposition.

[0050] Preferably, the deposition temperature of the atomic layer deposition is 140-160℃, for example, it can be 140℃, 145℃, 150℃, 155℃ or 160℃, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0051] Preferably, the precursor raw material of the atomic layer deposition includes trimethylaluminum and phosphoric acid.

[0052] Preferably, the ion storage layer is prepared by electrochemical deposition.

[0053] Preferably, the electron blocking layer is prepared by electron beam evaporation.

[0054] Preferably, the preparation method further comprises: preparing a two-dimensional material modification layer between the electrochromic layer and the first phosphate electrolyte layer.

[0055] Preferably, the two-dimensional material modification layer is prepared by plasma enhanced chemical vapor deposition and / or spin coating.

[0056] Preferably, the preparation method further comprises: preparing a thermoelectric conversion layer on the electron blocking layer.

[0057] Preferably, the thermoelectric conversion layer is prepared by hot pressing.

[0058] Preferably, the temperature of the hot pressing is 280-320℃, for example, it can be 280℃, 285℃, 290℃, 295℃, 300℃, 305℃, 310℃, 315℃ or 320℃, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0059] Preferably, the pressure of the hot pressing is 8-12MPa, for example, it can be 8MPa, 9MPa, 10MPa, 11MPa or 12MPa, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0060] Compared with the prior art, the present application has the following beneficial effects:

[0061] The electrochromic device provided by the present application has the advantages of improving the conductivity and stability of the device, realizing high ionic conductivity, response speed and long cycle life, and inhibiting the reverse migration of electrons and ions through the electron blocking layer, thereby realizing long-time color storage. BRIEF DESCRIPTION OF DRAWINGS

[0062] Figure 1 is a structural schematic diagram of a full solid-state electrochromic device based on a phosphate electrolyte provided in Example 1;

[0063] wherein 1, substrate; 2, transparent conductive layer; 3, electrochromic layer; 4, two-dimensional material modification layer; 5, phosphate electrolyte composite layer; 51, first phosphate electrolyte layer; 52, second phosphate electrolyte layer; 6, ion storage layer; 7, electron blocking layer; 8, thermoelectric conversion layer. DETAILED DESCRIPTION

[0064] The technical solutions of the present application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only to help understand the present application and should not be regarded as specific limitations on the present application.

[0065] Example 1

[0066] The present embodiment provides a full solid-state electrochromic device based on a phosphate electrolyte as shown in Figure 1 The full solid-state electrochromic device based on a phosphate electrolyte includes a substrate 1, and a transparent conductive layer 2, an electrochromic layer 3, a two-dimensional material modification layer 4, a phosphate electrolyte composite layer 5, an ion storage layer 6, an electron blocking layer 7 and a thermoelectric conversion layer 8 which are sequentially stacked on the substrate 1; the phosphate electrolyte composite layer 5 includes a first phosphate electrolyte layer 51 and a second phosphate electrolyte layer 52.

[0067] The transparent conductive layer 2 is a metal nanometer mesh layer formed on a transparent oxide layer. The material of the transparent oxide layer is ITO. The thickness of the transparent oxide layer is 50 nm. The mesh line diameter of the metal nanometer mesh layer is 90 nm, the mesh side length is 8 μm, and the metal material is silver. The thickness of the metal nanometer mesh layer is 65 nm. The total thickness of the transparent conductive layer is 115 nm.

[0068] The material of the electrochromic layer 3 is WO3, and the thickness is 350 nm.

[0069] The material of the two-dimensional material modification layer 4 is MoS2, and the thickness is 5 nm.

[0070] The material of the first phosphate electrolyte layer 51 is NaPO3, and the thickness is 400 nm.

[0071] The second phosphate electrolyte layer 52 is an atomic deposition AlPO4 layer, and the thickness is 80 nm.

[0072] The material of the ion storage layer 6 is NiO, and the thickness is 200 nm.

[0073] The material of the electron blocking layer 7 is ZrO2, and the thickness is 35 nm.

[0074] The material of the thermoelectric conversion layer 8 is Bi2Te3, and the thickness is 10 μm.

[0075] The preparation method of the all-solid-state electrochromic device comprises sequentially preparing a transparent conductive layer, an electrochromic layer, a two-dimensional material modification layer, a phosphate electrolyte composite layer, an ion storage layer, an electron blocking layer and a thermoelectric conversion layer on a substrate. Specifically, the following steps are included:

[0076] (1) Substrate pretreatment: the substrate glass is cleaned using oxygen plasma, the cleaning power is 100 W, and the time is 5 min;

[0077] (2) Preparation of a transparent conductive layer: a metal nanometer grid pattern is formed on the glass substrate by using a nano-imprint lithography method, then metal silver is deposited on the glass substrate by using an electron beam evaporation method to obtain a metal nanometer grid layer, and then an ITO layer is deposited on the metal nanometer grid layer by using a magnetron sputtering method, the process parameters of the magnetron sputtering method include: the working gas is a mixed gas of argon and oxygen (the volume ratio is 9:1), the power is 150 W, the substrate temperature is 200 ℃, and after the sputtering is completed, the substrate is annealed at 250 ℃ for 2 h in a nitrogen atmosphere;

[0078] (3) Preparation of an electrochromic layer: a WO3 layer is deposited on the ITO layer by using a magnetron sputtering method, and the process parameters include: the working gas is a mixed gas of argon and oxygen, and the power is 100 W;

[0079] (4) Preparation of a two-dimensional material modification layer: MoS2 is grown on the electrochromic layer by using a plasma-enhanced chemical deposition (CVD) method, and the process parameters include: the temperature is 800 ℃, and the working gas is a mixed gas of CH4 and H2;

[0080] (5) Preparation of a first phosphate electrolyte layer: a NaPO3 ceramic target is used as a target material, and a NaPO3 layer is deposited on the two-dimensional material modification layer by using a radio frequency magnetron sputtering method, the sputtering power is 200 W, and after the sputtering is completed, the substrate is annealed at 400 ℃ for 10 min to form a NaPO3 electrolyte layer with an amorphous glass phase structure;

[0081] (6) Preparation of a second phosphate electrolyte layer: trimethylaluminum (TMA) and phosphoric acid are used as precursors, and an AlPO4 electrolyte layer is deposited by using an atomic layer deposition method, the deposition temperature is 150 ℃, and the deposition is repeated 150 times to reach the target thickness;

[0082] (7) Preparation of an ion storage layer: a NiO layer is deposited on the electrolyte layer by using an electrochemical deposition method, and the working solution is a 0.1M NiCl2 solution;

[0083] (8) Preparation of electron blocking layer: ZrO2 layer is deposited on the ion storage layer by electron beam evaporation method, and the deposition rate is 0.5 angstrom / s;

[0084] (9) Preparation of thermoelectric conversion layer: Bi2Te3 powder is hot-pressed on the electron blocking layer, the hot-pressing temperature is 300 DEG C, and the hot-pressing pressure is 10 MPa;

[0085] (10) The prepared device is packaged with ultraviolet curing glue, and the edge is sealed with epoxy resin.

[0086] Example 2

[0087] The embodiment provides a full solid-state electrochromic device based on a phosphate electrolyte, which comprises a substrate, and a transparent conductive layer, an electrochromic layer, a two-dimensional material modification layer, a phosphate electrolyte composite layer, an ion storage layer, an electron blocking layer and a thermoelectric conversion layer which are sequentially stacked on the substrate; the phosphate electrolyte composite layer comprises a first phosphate electrolyte layer and a second phosphate electrolyte layer.

[0088] The transparent conductive layer is a metal nanometer grid layer formed on a transparent oxide layer. The material of the transparent oxide layer is ITO. The thickness of the transparent oxide layer is 30 nm. The grid line diameter of the metal nanometer grid layer is 100 nm, the grid side length is 5 mu m, and the metal material is silver. The thickness of the metal nanometer grid layer is 50 nm. The total thickness of the transparent conductive layer is 80 nm.

[0089] The material of the electrochromic layer is WO3, and the thickness is 500 nm.

[0090] The material of the two-dimensional material modification layer is MoS2, and the thickness is 10 nm.

[0091] The material of the first phosphate electrolyte layer is NaPO3, and the thickness is 300 nm.

[0092] The second phosphate electrolyte layer is an atomic deposition AlPO4 layer, and the thickness is 100 nm.

[0093] The material of the ion storage layer is NiO, and the thickness is 300 nm.

[0094] The material of the electron blocking layer is ZrO2, and the thickness is 20 nm.

[0095] The material of the thermoelectric conversion layer is Bi2Te3, and the thickness is 5 mu m.

[0096] The preparation method of the full solid-state electrochromic device is the same as that in example 1.

[0097] Example 3

[0098] The embodiment provides a full solid-state electrochromic device based on a phosphate electrolyte, which comprises a substrate, and a transparent conductive layer, an electrochromic layer, a two-dimensional material modification layer, a phosphate electrolyte composite layer, an ion storage layer, an electron blocking layer and a thermoelectric conversion layer which are sequentially stacked on the substrate; the phosphate electrolyte composite layer comprises a first phosphate electrolyte layer and a second phosphate electrolyte layer.

[0099] The transparent conductive layer is a metal nanometer grid layer formed on a transparent oxide layer. The material of the transparent oxide layer is ITO. The thickness of the transparent oxide layer is 70 nm. The grid line diameter of the metal nanometer grid layer is 80 nm, the grid side length is 10 μm, and the metal material is silver. The thickness of the metal nanometer grid layer is 80 nm. The total thickness of the transparent conductive layer is 150 nm.

[0100] The material of the electrochromic layer is WO3, and the thickness is 200 nm.

[0101] The material of the two-dimensional material modification layer is MoS2, and the thickness is 1 nm.

[0102] The material of the first phosphate electrolyte layer is NaPO3, and the thickness is 500 nm.

[0103] The second phosphate electrolyte layer is an atomic deposition AlPO4 layer, and the thickness is 50 nm.

[0104] The material of the ion storage layer is NiO, and the thickness is 100 nm.

[0105] The material of the electron blocking layer is ZrO2, and the thickness is 50 nm.

[0106] The material of the thermoelectric conversion layer is Bi2Te3, and the thickness is 20 μm.

[0107] Embodiment 4

[0108] The embodiment provides a full solid-state electrochromic device based on a phosphate electrolyte, which comprises a substrate, and a transparent conductive layer, an electrochromic layer, a two-dimensional material modification layer, a phosphate electrolyte composite layer, an ion storage layer, an electron blocking layer and a thermoelectric conversion layer which are sequentially stacked on the substrate; the phosphate electrolyte composite layer comprises a first phosphate electrolyte layer and a second phosphate electrolyte layer.

[0109] In the preparation method of the full solid-state electrochromic device, the two-dimensional material modification layer is replaced by growing graphene instead of growing MoS2, and the rest is the same as in Embodiment 1.

[0110] Embodiment 5

[0111] The embodiment provides a full solid-state electrochromic device based on a phosphate electrolyte, which comprises a substrate, and a transparent conductive layer, an electrochromic layer, a two-dimensional material modification layer, a phosphate electrolyte composite layer, an ion storage layer, an electron blocking layer and a thermoelectric conversion layer which are sequentially stacked on the substrate; the phosphate electrolyte composite layer comprises a first phosphate electrolyte layer and a second phosphate electrolyte layer.

[0112] The preparation method of the all-solid-state electrochromic device does not prepare a two-dimensional material modification layer, and the rest is the same as example 1.

[0113] Example 6

[0114] The present example provides an all-solid-state electrochromic device based on a phosphate electrolyte. Compared with example 1, the transparent conductive layer with the same thickness is replaced by an ITO transparent oxide layer, that is, no metal nanometer mesh layer is provided, and the rest is the same as example 1.

[0115] The preparation method of the all-solid-state electrochromic device does not prepare a metal nanometer mesh layer, and directly sputters an ITO layer on the glass substrate, and the rest is the same as example 1.

[0116] Example 7

[0117] The present example provides an all-solid-state electrochromic device based on a phosphate electrolyte. Compared with example 1, the material of the first phosphate electrolyte layer is replaced by Na3PO4, and the rest is the same as example 1.

[0118] The preparation method of the all-solid-state electrochromic device replaces the target material with Na3PO4, and the rest is the same as example 1.

[0119] Comparative example 1

[0120] The present comparative example provides an all-solid-state electrochromic device based on a phosphate electrolyte. Compared with example 1, no second phosphate electrolyte layer is provided, and the rest is the same as example 1.

[0121] The preparation method of the all-solid-state electrochromic device does not prepare a second phosphate electrolyte layer, and the rest is the same as example 1.

[0122] Comparative example 2

[0123] The present comparative example provides an all-solid-state electrochromic device based on a phosphate electrolyte. Compared with example 1, no electron blocking layer is provided, and the rest is the same as example 1.

[0124] The preparation method of the all-solid-state electrochromic device does not prepare an electron blocking layer, and the rest is the same as example 1.

[0125] Performance test

[0126] The all-solid-state electrochromic devices provided by the examples and comparative examples are respectively tested for device performance.

[0127] Ion conductivity: The Nyquist diagram of the device is tested by electrochemical impedance spectrum tester, and the ion conductivity is calculated.

[0128] Response speed test: a jump voltage of 3V is applied to the device, the transmittance change at a wavelength of 600nm is measured, and the time for the transmittance change to reach 90% is the response time.

[0129] Cycle life test: the device is subjected to constant voltage cycle test, the coloring voltage is 3V, and the bleaching voltage is-3V.

[0130] Open circuit memory effect: after coloring the device, the circuit is disconnected, and the bleaching time is recorded.

[0131] The results are shown in Table 1.

[0132] Table 1

[0133]

[0134] As can be seen from Table 1:

[0135] The electrochromic device of the present application cooperatively improves the conductivity and stability performance of the electrochromic device through the synergistic effect of the composite phosphate electrolyte layer and the functional layer, significantly improves the ionic conductivity of the device, reduces the response time, meets the rapid color change demand, increases the cycle life, improves the long-term stability of the device, prolongs the bleaching time, realizes long-time color storage, and solves the problems of conductivity, stability, response speed and storage capacity of the electrochromic device.

[0136] ①Through the composite structure design of the first phosphate electrolyte layer sodium metaphosphate and the second phosphate electrolyte layer aluminum phosphate, sodium metaphosphate can provide smooth Na + migration channel to ensure high ion conduction, and aluminum phosphate can fill the inner layer pinhole defects and enhance the mechanical and chemical stability, and the two can cooperatively solve the technical difficulties of high conductivity and high stability of the electrochromic device. Compared with Comparative Example 1 and Example 1, when there is no second phosphate electrolyte layer, the ionic conductivity is significantly reduced by more than 50%, the response time is prolonged, the efficiency is greatly reduced, and the cycle life is reduced, and the stability is significantly degraded.

[0137] ②Through the synergistic cooperation of each functional layer, the performance of the device is further improved. Compared with Example 1 and Examples 4-5, when graphene is used instead of MoS2, the conductivity and response performance decrease slightly, indicating that the interface matching degree of MoS2 and phosphate electrolyte is better; when the two-dimensional material modification layer is not set, the ionic conductivity and cycle life decrease, indicating that the two-dimensional material modification layer can reduce the interface resistance between the electrochromic layer and the electrolyte layer and reduce the interface side reaction. Compared with Example 1 and Example 6, it is shown that the metal nanomesh can significantly improve the conductivity efficiency while ensuring the light transmittance, solving the problem of "difficult balance between high light transmittance and high conductivity" of single ITO layer. Compared with Example 1 and Example 7, the crystal structure of Na3PO4 can increase the Na +The migration energy barrier is removed, and the amorphous structure of sodium metaphosphate is more suitable for the high ion conduction requirement. Comparing Example 1 with Comparative Example 2, no electronic blocking layer is arranged, and the fading time is reduced sharply, which indicates that the electronic blocking layer can inhibit the reverse migration and realize long-time color storage.

[0138] In summary, the electrochromic device provided by the application considers the improvement of the conductivity and stability of the device by designing a composite phosphate electrolyte layer, realizes high ion conductivity, response speed and long cycle life, and at the same time, through the electronic blocking layer, the reverse migration of electrons and ions is inhibited, and long-time color storage is realized.

[0139] The applicant declares that the above is only a specific embodiment of the application, but the protection scope of the application is not limited to this. It should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed by the application can be easily thought of by any person skilled in the art, and falls within the protection scope and disclosure scope of the application.

Claims

1. A phosphate electrolyte-based all-solid-state electrochromic device, characterized by, The all-solid-state electrochromic device comprises a substrate, and a transparent conductive layer, an electrochromic layer, a phosphate electrolyte composite layer, an ion storage layer and an electron blocking layer which are sequentially stacked on the substrate; The phosphate electrolyte composite layer comprises a first phosphate electrolyte layer and a second phosphate electrolyte layer.

2. The all-solid-state electrochromic device according to claim 1, characterized in that, The thickness of the transparent conductive layer is 80-150 nm; Preferably, the transparent conductive layer comprises a transparent oxide layer on which a metal nanometer mesh layer is formed; Preferably, the metal of the metal nanometer mesh layer comprises silver and / or copper; Preferably, the mesh size of the metal nanometer mesh layer is 5-10 μm; Preferably, the diameter of the mesh line of the metal nanometer mesh layer is 80-100 nm; Preferably, the thickness of the metal nanometer mesh layer is 50-80 nm; Preferably, the material of the transparent oxide layer comprises ITO; Preferably, the thickness of the transparent oxide layer is 30-70 nm.

3. The all-solid-state electrochromic device according to claim 1 or 2, characterized in that, The material of the electrochromic layer comprises at least one of WO3, MoO3 or TiO2; Preferably, the thickness of the electrochromic layer is 200-500 nm.

4. The all-solid-state electrochromic device according to any one of claims 1 to 3, characterized in that, The material of the first phosphate electrolyte layer comprises sodium metaphosphate; Preferably, the thickness of the first phosphate electrolyte layer is 300-500 nm; Preferably, the material of the second phosphate electrolyte layer comprises AlPO4; Preferably, the thickness of the second phosphate electrolyte layer is 50-100 nm.

5. The all-solid-state electrochromic device according to any one of claims 1 to 4, characterized in that, The material of the ion storage layer comprises a metal oxide; Preferably, the metal oxide comprises a nickel-based oxide and / or a vanadium-based oxide; Preferably, the nickel-based oxide comprises NiO; Preferably, the vanadium-based oxide comprises V2O5; Preferably, the thickness of the ion storage layer is 100-300 nm.

6. The all-solid-state electrochromic device according to any one of claims 1 to 5, characterized in that, The material of the electron blocking layer comprises ZrO2; Preferably, the thickness of the electron blocking layer is 20-50 nm.

7. The all-solid-state electrochromic device according to any one of claims 1 to 6, characterized in that, The all-solid-state electrochromic device further comprises a two-dimensional material modification layer which is stacked between the electrochromic layer and the composite phosphate electrolyte layer; Preferably, the material of the two-dimensional material modification layer comprises graphene and / or MoS2; Preferably, the thickness of the two-dimensional material modification layer is 1-10 nm.

8. The all-solid-state electrochromic device according to any one of claims 1 to 7, characterized in that, The all-solid-state electrochromic device further comprises a thermoelectric conversion layer which is stacked on the electron blocking layer; Preferably, the thickness of the thermoelectric conversion layer is 5-20 μm; Preferably, the material of the thermoelectric conversion layer comprises Bi2Te3.

9. A method for the preparation of a phosphate-based electrolyte based all-solid- state electrochromic device according to any one of claims 1-8, characterized in that, The preparation method comprises sequentially preparing a transparent conductive layer, an electrochromic layer, a first phosphate electrolyte layer, a second phosphate electrolyte layer, an ion storage layer and an electron blocking layer on a substrate.

10. The method of claim 9, wherein, The preparation method of the transparent conductive layer comprises: first forming a mesh pattern on the substrate by using a nanoimprint lithography method, forming a metal nanometer mesh on the substrate by using an electron beam evaporation deposition method, depositing a transparent oxide layer on the metal nanometer mesh by using a magnetron sputtering method, and performing annealing treatment on the substrate on which the transparent conductive layer is deposited; Preferably, the temperature of the annealing treatment is 240-260 ℃; Preferably, the first phosphate electrolyte layer is prepared by using a radio frequency magnetron sputtering method; Preferably, the second phosphate electrolyte layer is prepared by atomic layer deposition; Preferably, the deposition temperature of the atomic layer deposition is 140-160℃; Preferably, the precursor raw material of the atomic layer deposition comprises trimethylaluminum and phosphoric acid; Preferably, the ion storage layer is prepared by electrochemical deposition; Preferably, the electron blocking layer is prepared by electron beam evaporation; Preferably, the preparation method further comprises: preparing a two-dimensional material modification layer between the electrochromic layer and the first phosphate electrolyte layer; Preferably, the two-dimensional material modification layer is prepared by plasma enhanced chemical vapor deposition and / or spin coating; Preferably, the preparation method further comprises: preparing a thermoelectric conversion layer on the electron blocking layer; Preferably, the thermoelectric conversion layer is prepared by hot pressing; Preferably, the temperature of the hot pressing is 280-320℃; Preferably, the pressure of the hot pressing is 8-12MPa.

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