Single-atom cobalt-doped oxygen vacancy v2o5 electrochromic material, preparation method and application thereof

Abstract

The application discloses a single-atom cobalt-doped oxygen vacancy V2O5 electrochromic material and a preparation method and application thereof, relates to the technical field of functional electrochemical materials, and comprises an oxygen vacancy-enriched vanadium pentoxide base body, cobalt dispersed in a vanadium pentoxide crystal lattice, and a conductive polymer layer coated on the surface. 5‑x The thin film material is a vanadium pentoxide base body with an oxygen vacancy structure, the conductive polymer layer is poly(5-formylindole), namely P5FIn, the cobalt is dispersed in the V2O 5‑x crystal lattice structure in the form of single atoms to form a composite structure of P5FIn / Co-V2O 5‑x The prepared material can be applied to electrochromic supercapacitors and other devices. The material has excellent optical modulation performance and electrochemical energy storage performance, and exhibits a faster response speed, a higher specific capacitance and good cycle stability in the electrochromic supercapacitors and other devices.

Description

Technical Field

[0001] This invention relates to the field of functional electrochemical materials technology, specifically to a single-atom cobalt-doped oxygen vacancy V2O5 electrochromic material, its preparation method, and its application. Background Technology

[0002] With the rapid development of intelligent buildings, flexible electronic devices, and new energy management systems, multifunctional devices capable of simultaneously achieving optical control and energy storage have gradually become an important research direction in the field of materials science. Electrochromic materials can undergo reversible changes in color or transmittance under the action of an applied electric field, thus showing broad application prospects in fields such as smart windows, information displays, and optical control. In recent years, combining electrochromic functionality with the energy storage characteristics of supercapacitors to form electrochromic supercapacitors has attracted widespread attention from researchers. This not only enables efficient energy storage but also allows for a direct reflection of the device's charge and discharge state through color changes.

[0003] Among numerous electrochromic material systems, transition metal oxides have been extensively studied due to their reversible redox reactivity and high theoretical electrochemical performance. Vanadium pentoxide (V₂O₅), with its layered crystal structure and multivalent state transition characteristics, can achieve reversible ion insertion and extraction, showing promising application potential in electrochromic and energy storage fields. However, traditional V₂O₅ materials still suffer from poor electronic conductivity, slow ion diffusion kinetics, and insufficient cycling stability, which to some extent limits their application in high-performance electrochromic energy storage devices.

[0004] To address these issues, researchers have employed strategies such as defect engineering, heteroelement doping, and conductive polymer composites to modulate materials. For instance, introducing oxygen vacancies into oxide structures can increase active sites and enhance electron transport capabilities, while single-atom metal doping can adjust the electronic structure of materials and promote electrochemical reaction kinetics. Meanwhile, conductive polymers possess excellent electrical conductivity and structural flexibility; combining them with metal oxides can construct continuous electron transport networks and improve interfacial ion transport performance. However, existing material systems still have limitations in terms of structural stability, conductivity, and electrochromic response speed. Therefore, developing a composite material system with structural stability, high electron and ion transport efficiency, and excellent electrochromic and energy storage properties is of great significance. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a single-atom cobalt-doped oxygen-vacancy V2O5 electrochromic material, its preparation method, and its application, thereby solving the problems of low conductivity, slow ion transport rate, and insufficient cycle stability mentioned in the background technology.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The present invention provides a single-atom cobalt-doped oxygen vacancy V2O5 electrochromic material, comprising a vanadium pentoxide matrix enriched with oxygen vacancies, cobalt dispersed in a vanadium pentoxide lattice, and a conductive polymer layer coated on its surface.

[0008] The vanadium pentoxide matrix is ​​V2O with an oxygen vacancy structure. 5-x Thin film materials in which oxygen vacancies are used to improve the material’s electron transport capability and ion diffusion rate;

[0009] The conductive polymer layer is made of poly(5-formylindole), i.e. P5FIn, which forms a continuous porous conductive network structure on the material surface.

[0010] The cobalt is dispersed in V2O in the form of single atoms. 5-x In the crystal lattice structure, P5FIn / Co-V2O is formed. 5-x The composite structure.

[0011] To further optimize this technical solution, the cobalt single atoms are dispersed in the V2O5 lattice structure through substitution or embedding, forming a Co-OV coordination structure.

[0012] To further optimize this technical solution, the poly(5-formylindole) forms a continuous porous conductive network structure and uniformly covers Co-V2O. 5-x The surface is used to construct continuous electron / ion transport channels.

[0013] To further optimize this technical solution, the cobalt single atom in V2O 5-x The content in the crystal structure is 0.01–5 at.

[0014] A method for preparing a single-atom cobalt-doped oxygen-vacancy V2O5 electrochromic material, based on the above-mentioned single-atom cobalt-doped oxygen-vacancy V2O5 electrochromic material, includes the following preparation steps: S1, V2O 5-x Thin film material preparation; A vanadium pentoxide precursor solution was electrodeposited onto a conductive substrate to obtain a V₂O₅ thin film, which was then subjected to reduction or thermal treatment to form V₂O₅ containing oxygen vacancies. 5-x structure; S2, cobalt single-atom doping; The V₂O₅ film obtained in step S1 is immersed in a cobalt-containing precursor solution, followed by drying and heat treatment to disperse and embed cobalt single atoms into the V₂O₅ lattice, thus obtaining Co-V₂O. 5-x structure; S3, conductive polymer deposition; The Co-V2O obtained in step S2 5-x The structure was placed in an electrolyte containing a 5-formylindole monomer and electrochemically polymerized in Co-V2O. 5-x Poly(5-formylindole) is deposited on the surface to form a conductive polymer layer, thereby obtaining P5FIn / Co-V2O. 5-x Composite electrochromic materials, namely single-atom cobalt-doped oxygen vacancy V2O5 electrochromic materials.

[0015] To further optimize this technical solution, in step S1, the vanadium pentoxide precursor solution is formed by dissolving ammonium metavanadate in deionized water and fully dissolving it under magnetic stirring.

[0016] To further optimize this technical solution, in step S2, the cobalt salt precursor is one or more of cobalt nitrate, cobalt chloride, or cobalt acetate.

[0017] To further optimize this technical solution, in step S2, the heat treatment temperature is 200-500℃ and the heat treatment time is 1-5h.

[0018] An application of a single-atom cobalt-doped oxygen vacancy V2O5 electrochromic material, based on the above-mentioned single-atom cobalt-doped oxygen vacancy V2O5 electrochromic material, wherein the electrochromic material is applied in an electrochromic device.

[0019] To further optimize this technical solution, the electrochromic device is an electrochromic supercapacitor, which includes electrodes, an electrolyte, and a single-atom cobalt-doped oxygen vacancy V2O5 electrochromic material disposed on the electrode surface.

[0020] Compared with the prior art, the present invention provides a single-atom cobalt-doped oxygen-vacancy V2O5 electrochromic material, its preparation method, and its application, which has the following beneficial effects: (1) By introducing oxygen vacancies and doping cobalt single atoms into the vanadium pentoxide structure, the present invention can effectively regulate the electronic structure of the material and increase the active sites, thereby improving the electronic conductivity and ion transport rate of the material and significantly improving the kinetic performance of the electrochromic reaction.

[0021] (2) The present invention uses single-atom cobalt-doped V2O 5-x Introducing the conductive polymer poly(5-formylindole) into the surface of the structure forms a continuous conductive network structure, which not only promotes the coordinated transport of electrons and ions, but also effectively inhibits structural damage during electrochemical cycling, thereby improving the cycling stability of the material.

[0022] (3) This invention constructs a multi-level composite electrochromic material through the synergistic effect of oxygen vacancy structure, single-atom metal sites and conductive polymer layer, which simultaneously possesses excellent optical modulation performance and electrochemical energy storage performance, and exhibits fast response speed, high specific capacitance and good cycle stability in devices such as electrochromic supercapacitors.

[0023] (4) The preparation method provided by the present invention is simple and controllable, and is suitable for large-scale preparation. It provides a new material design idea and technical approach for constructing high-performance electrochromic energy storage devices. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the preparation method of the single-atom cobalt-doped oxygen vacancy V2O5 electrochromic material proposed in this invention; Figure 2 These are scanning electron microscope (SEM) images of different materials used in this invention. Figure 3 This is a transmission electron microscope (TEM) or HAADF-STEM structural image of the single-atom cobalt-doped oxygen vacancy V2O5 electrochromic material proposed in this invention. Figure 4 The elemental distribution diagram of the single-atom cobalt-doped oxygen vacancy V2O5 electrochromic material proposed in this invention is shown. Figure 5 The electrochemical performance test diagram of the single-atom cobalt-doped oxygen vacancy V2O5 electrochromic material proposed in this invention is shown. Figure 6 The optical transmittance curves and color change diagrams of the single-atom cobalt-doped oxygen vacancy V2O5 electrochromic material proposed in this invention are shown in the present invention. Detailed Implementation

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0027] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.

[0029] See Figure 1-6 A single-atom cobalt-doped oxygen vacancy V2O5 electrochromic material comprises a vanadium pentoxide matrix enriched with oxygen vacancies, cobalt dispersed in a vanadium pentoxide lattice, and a conductive polymer layer coated on its surface.

[0030] in: The vanadium pentoxide matrix is ​​V2O with an oxygen vacancy structure. 5-x Thin film materials.

[0031] The conductive polymer layer is made of poly(5-formylindole), i.e., P5FIn; the poly(5-formylindole) forms a continuous porous conductive network structure and uniformly covers Co-V2O. 5-x The surface is used to construct continuous electron / ion transport channels.

[0032] The cobalt is dispersed in V2O in the form of single atoms. 5-x In the crystal lattice structure, it is dispersed in the V2O5 crystal structure through substitution or intercalation, forming a Co-OV coordination structure, and finally forming P5FIn / Co-V2O. 5-x The composite structure. The cobalt single atom in V2O 5-x The content in the crystal structure is 0.01–5 at.

[0033] A method for preparing a single-atom cobalt-doped oxygen-vacancy V2O5 electrochromic material, based on the above-mentioned single-atom cobalt-doped oxygen-vacancy V2O5 electrochromic material, includes the following preparation steps: S1, V2O 5-x Thin film material preparation; A vanadium pentoxide precursor solution was electrodeposited onto a conductive substrate to obtain a V₂O₅ thin film, which was then subjected to reduction or thermal treatment to form V₂O₅ containing oxygen vacancies. 5-x structure.

[0034] Specifically, the vanadium pentoxide precursor solution is formed by dissolving ammonium metavanadate in deionized water and fully dissolving it under magnetic stirring.

[0035] S2, cobalt single-atom doping; The V₂O₅ film obtained in step S1 is immersed in a cobalt-containing precursor solution, followed by drying and heat treatment. The heat treatment temperature is 200-500℃, and the heat treatment time is 1-5 hours. This disperses cobalt single atoms and embeds them into the V₂O₅ lattice, yielding Co-V₂O₅. 5-x structure.

[0036] Specifically, the cobalt salt precursor is one or more of cobalt nitrate, cobalt chloride, or cobalt acetate.

[0037] S3, conductive polymer deposition; The Co-V2O obtained in step S2 5-x The structure was placed in an electrolyte containing a 5-formylindole monomer and electrochemically polymerized in Co-V2O. 5-x Poly(5-formylindole) is deposited on the surface to form a conductive polymer layer, thereby obtaining P5FIn / Co-V2O. 5-x Composite electrochromic materials, namely single-atom cobalt-doped oxygen vacancy V2O5 electrochromic materials.

[0038] Example 1: A method for preparing a single-atom cobalt-doped oxygen-vacancy V2O5 electrochromic material includes the following preparation steps:

[0039] S1, V2O 5-x Thin film material preparation; Ammonium metavanadate was weighed and dissolved in deionized water, and the solution was fully dissolved under magnetic stirring to form a homogeneous precursor solution. Subsequently, using a conductive glass substrate as the working electrode, an electrodeposition reaction was carried out under constant potential conditions, causing vanadium pentoxide to gradually deposit on the surface of the conductive substrate to form a uniform thin film structure, yielding a V₂O₅ thin film. This film was then further processed by reduction or heat treatment to form V₂O₅ containing oxygen vacancies. 5-x Structure. After electrodeposition, the resulting sample is heat-treated in an air atmosphere to promote the formation of V₂O₅ crystal structure and introduce oxygen vacancies into the material, thereby obtaining V₂O₅. 5-x Thin film materials.

[0040] S2, cobalt single-atom doping; Cobalt nitrate was dissolved in deionized water to prepare a cobalt-containing precursor solution. The V₂O₅ film obtained in step S1 was then immersed in the cobalt-containing precursor solution and allowed to stand or be gently stirred at room temperature for a period of time to allow cobalt ions to be fully adsorbed onto the V₂O₅ film. 5-x Surface and lattice defect sites were identified. Subsequently, drying and heat treatment were performed at temperatures of 200-500℃ for 1-5 hours to disperse and embed cobalt single atoms within the V₂O₅ lattice, yielding Co-V₂O₅. 5-x structure.

[0041] S3, conductive polymer deposition; The Co-V2O obtained in step S2 5-x The structure was placed in an electrolyte containing a 5-formylindole monomer and electrochemically polymerized in Co-V2O. 5-x Poly(5-formylindole) is deposited on the surface to form a conductive polymer layer, thereby obtaining P5FIn / Co-V2O. 5-x Composite electrochromic materials, namely single-atom cobalt-doped oxygen vacancy V2O5 electrochromic materials.

[0042] In the above preparation process, by controlling the electrodeposition time, the concentration of the cobalt-containing precursor solution, and the electrochemical polymerization conditions, the structure and properties of the composite material can be effectively controlled, thereby obtaining a composite material with good conductivity and electrochromic properties.

[0043] In this embodiment, the obtained V2O 5-x Co-V2O 5-x and P5FIn / Co-V2O 5-x The material was characterized in terms of structure and morphology. The surface morphology of the material was observed by scanning electron microscopy (SEM), and the results showed that a uniform porous structure was formed on the surface of the composite material, which is conducive to the rapid diffusion and transport of electrolyte ions.

[0044] Further analysis of the material using transmission electron microscopy (TEM) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) revealed that cobalt is dispersed in V₂O in single-atom form. 5-x In the crystal lattice structure, stable active sites are formed on the material surface.

[0045] Meanwhile, the elemental distribution of the material was tested by energy dispersive spectroscopy (EDS). The results showed that V, O, Co, C and N elements were uniformly distributed in the composite material, indicating that the conductive polymer and inorganic material were successfully combined to form a stable composite structure.

[0046] The above P5FIn / Co-V2O 5-x The composite material was used as the electrode material to assemble an electrochromic device, and its electrochromic performance was tested on an electrochemical workstation. The experimental results show that the material can exhibit obvious color changes under an applied voltage and has good optical modulation capabilities.

[0047] The transmittance variation curves of the material were recorded under different voltage conditions. The results showed that the composite material has a large optical modulation range in the visible light region and can complete the coloring and fading process in a short time, exhibiting a fast electrochromic response speed.

[0048] Furthermore, the electrochemical performance of the material was tested, including cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). The test results showed that the composite material has high electrochemical activity and good electron and ion transport capabilities.

[0049] In the cycle stability test, after multiple charge-discharge cycles, the composite material can still maintain relatively stable electrochromic properties and electrochemical energy storage properties, indicating that the material has good structural stability and cycle life.

[0050] Therefore, the P5FIn / Co-V2O prepared in this embodiment 5-x Composite materials can simultaneously achieve electrochromic and electrochemical energy storage functions, and have good application potential in fields such as electrochromic supercapacitors and visual energy storage devices.

[0051] Example 2: P5FIn / Co-V2O with different cobalt doping levels 5-x Preparation of composite materials: The preparation method in this embodiment is basically the same as that in Example 1, except that the concentration of the cobalt salt solution, i.e., the cobalt-containing precursor solution, used in step S2 is different. By adjusting the concentration of the cobalt nitrate solution, the doping amount of cobalt is controlled, thereby studying the effect of cobalt doping amount on the material structure and properties.

[0052] Co-V2O with different cobalt contents was prepared according to the above method. 5-x The material was subjected to electrochemical polymerization deposition of a poly(5-formylindole) conductive polymer layer on its surface, thereby obtaining a series of P5FIn / Co-V2O materials. 5-x Composite materials.

[0053] Electrochromic properties of the above materials were tested, and the results showed that, within an appropriate range of cobalt doping, the composite material could exhibit a larger optical modulation range and a faster coloring / fading response speed.

[0054] Example 3: Preparation of composite materials under different electrochemical polymerization conditions: This embodiment is basically the same as Example 1, except that the electrochemical polymerization conditions in step S3 are different. The thickness and structure of the poly(5-formylindole) conductive polymer layer are controlled by changing the electrochemical polymerization potential range, scan rate, or polymerization time.

[0055] The results show that, under appropriate polymerization conditions, conductive polymers can be synthesized in Co-V2O. 5-x A uniform and dense conductive layer is formed on the surface of the material, thereby further improving the electron transport capability and electrochromic stability of the composite material.

[0056] Comparative Example 1: The material was prepared according to the method of Example 1, but without adding cobalt salt solution in step S2, thereby obtaining cobalt-free V2O. 5-x The material was used to deposit a poly(5-formylindole) conductive polymer layer on its surface via electrochemical polymerization.

[0057] Comparative Example 2: The material was prepared according to the method of Example 1, but without the electrochemical polymerization reaction in step S3, thus obtaining Co-V2O. 5-x Material.

[0058] The electrochromic and electrochemical properties of the composite materials obtained in Examples 1-3 and Comparative Examples 1-2 were compared. The results showed that the P5FIn / Co-V2O prepared in this invention... 5-x The composite material is significantly superior to the material in the comparative example in terms of optical modulation capability, electrochromic response speed, and cycle stability.

[0059] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A single-atom cobalt-doped oxygen-vacancy V₂O₅ electrochromic material, characterized in that, It consists of a vanadium pentoxide matrix enriched with oxygen vacancies, cobalt dispersed in the vanadium pentoxide lattice, and a conductive polymer layer coated on its surface. The vanadium pentoxide matrix is ​​V2O with an oxygen vacancy structure. 5-x Thin film materials; The conductive polymer layer is made of poly(5-formylindole), i.e., P5FIn; The cobalt is dispersed in V2O in the form of single atoms. 5-x In the crystal lattice structure, P5FIn / Co-V2O is formed. 5-x The composite structure.

2. The single-atom cobalt-doped oxygen-vacancy V₂O₅ electrochromic material according to claim 1, characterized in that, The cobalt single atoms are dispersed in the V2O5 lattice structure through substitution or embedding, forming a Co-OV coordination structure.

3. The single-atom cobalt-doped oxygen-vacancy V₂O₅ electrochromic material according to claim 1, characterized in that, The poly(5-formylindole) forms a continuous porous conductive network structure and is uniformly covered by Co-V2O. 5-x The surface is used to construct continuous electron / ion transport channels.

4. The single-atom cobalt-doped oxygen-vacancy V₂O₅ electrochromic material according to claim 1, characterized in that, The cobalt single atom in V2O 5-x The content in the crystal structure is 0.01–5 at.

5. A method for preparing a single-atom cobalt-doped oxygen-vacancy V₂O₅ electrochromic material, comprising the preparation of the single-atom cobalt-doped oxygen-vacancy V₂O₅ electrochromic material according to any one of claims 1-4, characterized in that, The preparation steps include the following: S1, V2O 5-x Thin film material preparation; A vanadium pentoxide precursor solution was electrodeposited onto a conductive substrate to obtain a V₂O₅ thin film, which was then subjected to reduction or thermal treatment to form V₂O₃ containing oxygen vacancies. 5-x structure; S2, cobalt single-atom doping; The V₂O₅ film obtained in step S1 is immersed in a cobalt-containing precursor solution, followed by drying and heat treatment to disperse and embed cobalt single atoms into the V₂O₅ lattice, thus obtaining Co-V₂O. 5-x structure; S3, conductive polymer deposition; The Co-V2O obtained in step S2 5-x The structure was placed in an electrolyte containing a 5-formylindole monomer and electrochemically polymerized in Co-V2O. 5-x Poly(5-formylindole) is deposited on the surface to form a conductive polymer layer, thereby obtaining P5FIn / Co-V2O. 5-x Composite electrochromic materials, namely single-atom cobalt-doped oxygen vacancy V2O5 electrochromic materials.

6. The method for preparing a single-atom cobalt-doped oxygen-vacancy V₂O₅ electrochromic material according to claim 5, characterized in that, In step S1, the vanadium pentoxide precursor solution is formed by dissolving ammonium metavanadate in deionized water and fully dissolving it under magnetic stirring.

7. The method for preparing a single-atom cobalt-doped oxygen-vacancy V₂O₅ electrochromic material according to claim 5, characterized in that, In step S2, the cobalt salt precursor is one or more of cobalt nitrate, cobalt chloride, or cobalt acetate.

8. The method for preparing a single-atom cobalt-doped oxygen-vacancy V₂O₅ electrochromic material according to claim 5, characterized in that, In step S2, the heat treatment temperature is 200-500℃ and the heat treatment time is 1-5h.

9. An application of a single-atom cobalt-doped oxygen-vacancy V₂O₅ electrochromic material, based on the single-atom cobalt-doped oxygen-vacancy V₂O₅ electrochromic material according to claims 1-8, characterized in that, The electrochromic material is used in electrochromic devices.

10. The application of the single-atom cobalt-doped oxygen-vacancy V₂O₅ electrochromic material according to claim 9, characterized in that, The electrochromic device is an electrochromic supercapacitor, which includes electrodes, an electrolyte, and a single-atom cobalt-doped oxygen vacancy V2O5 electrochromic material as described in any one of claims 1-8 disposed on the electrode surface.

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