Nickel-manganese bimetallic hydroxide, oxide electrochromic thin films, their preparation and applications

Abstract

This invention relates to a nickel-manganese bimetallic hydroxide / oxide electrochromic thin film, its preparation, and its application. The electrochromic thin film of this invention is directly grown on the surface of fluorine-doped tin dioxide (FTO) conductive glass via a hydrothermal method. The specific steps are as follows: First, nickel source, manganese source, urea, and ammonium fluoride are dissolved in deionized water, then transferred to a hydrothermal reactor. An FTO conductive glass is placed in the reactor with its conductive side facing down. After a period of constant-temperature hydrothermal reaction, it is naturally cooled to room temperature. The FTO conductive glass is then removed from the reactor, cleaned, and dried to obtain the nickel-manganese bimetallic hydroxide electrochromic thin film. After calcination at a certain temperature, a nickel-manganese bimetallic oxide electrochromic thin film is obtained. Compared with single nickel oxide and manganese oxide, the NiMnLDH thin film of this invention exhibits a larger light modulation amplitude in the visible light region and higher transmittance in the faded state, making it applicable to electrochromism and related fields.

Description

Technical Field

[0001] This invention relates to the field of electrochromic thin film preparation technology, and in particular to a nickel-manganese bimetallic hydroxide and oxide electrochromic thin film, its preparation and application. Background Technology

[0002] Electrochromism refers to the phenomenon where some materials undergo reversible changes in valence state and chemical composition under the influence of an external electric field, resulting in reversible changes in their optical properties or appearance color. Electrochromic materials can be broadly classified into inorganic and organic electrochromic materials. Among them, inorganic metal oxides are some of the earliest and most widely studied electrochromic materials, possessing advantages such as high color contrast, good cycle stability, strong adhesion, and good thermal stability. Typical examples include WO3, Prussian blue (PB), and nickel oxide. WO3, as the earliest and most widely studied inorganic electrochromic material, has been widely applied in the electrochromic industry. However, WO3 can only switch between colorless and blue (ACS Appl. Mater. Interfaces 2021, 13, 11067; Electrochim. Acta 2020, 353, 136446), which does not meet people's preferences, and prolonged exposure to blue can induce depression. NiO and MnO2, as typical anodizing materials (Sci. China Chem. 2017, 60, 54; J. Mater. Chem. C, 2017, 5, 1758; Adv. Mater. Interfaces 2019, 6, 1901038), can vary between light brown and brown, which are the most comfortable neutral tones for the human eye. However, NiO and MnO2 films still retain color (pale yellow or light brown) in their faded state, preventing them from achieving complete transparency. This results in a narrow and small light modulation range, which cannot meet practical needs.

[0003] Furthermore, NiMnLDH is a layered bimetallic hydroxide, typically with a nanosheet structure. Both Ni and Mn have variable valence states, and the substitution of Ni(II) by Mn(III) leads to a high dispersion of Ni in the host layer, thereby improving the utilization rate of Ni. Therefore, NiMnLDH and nickel-manganese bimetallic oxides are commonly used as electrode materials for batteries or supercapacitors. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a nickel-manganese bimetallic hydroxide and oxide electrochromic thin film, as well as its preparation and application. This invention employs a one-step hydrothermal method to prepare a nickel-manganese bimetallic hydroxide (NiMnLDH) electrochromic thin film on the surface of FTO conductive glass. After calcination, a nickel-manganese bimetallic oxide electrochromic thin film is obtained. This film is then directly grown on the surface of fluorine-doped tin dioxide (FTO) conductive glass using a hydrothermal method, achieving broad-spectrum, large-amplitude modulation (switching between colorless and transparent and brownish-black, meeting the neutral hue required by the human eye), thereby more effectively saving energy. The preparation method is simple, yielding electrochromic films with good stability, high adhesion, and uniformity. The NiMnLDH and nickel-manganese bimetallic oxide thin films of this invention can simultaneously achieve color change and energy storage, showing broad application prospects in the fields of electrochromic energy storage and visualized electrochemical energy storage.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] One objective of this invention is to provide a method for preparing a nickel-manganese bimetallic hydroxide electrochromic thin film, the specific steps of which are as follows:

[0007] S1. Dissolve nickel source, manganese source, urea and ammonium fluoride in deionized water to obtain a hydrothermal reaction precursor solution;

[0008] S2. FTO conductive glass is added to the hydrothermal reaction precursor solution obtained in step S1, and a hydrothermal reaction is carried out to obtain a nickel-manganese bimetallic hydroxide (NiMnLDH) electrochromic film.

[0009] Further, in step S1, the nickel source is selected from nickel chloride hexahydrate, nickel acetate tetrahydrate, or nickel sulfate hexahydrate; the molar concentration of the nickel source in the hydrothermal reaction precursor solution is 0.005–0.025 mol / L.

[0010] Further, in step S1, the manganese source is selected from manganese nitrate tetrahydrate, manganese sulfate monohydrate, or manganese acetate tetrahydrate; the molar ratio of nickel to manganese in the hydrothermal reaction precursor solution is 1:5 to 5:1.

[0011] Furthermore, in step S1, the mass concentration of ammonium fluoride in the hydrothermal reaction precursor solution is 2–10 g / L.

[0012] Furthermore, in step S1, the mass concentration of urea in the hydrothermal reaction precursor solution is 2–10 g / L.

[0013] Further, in step S2, the hydrothermal reaction precursor solution obtained in step S1 is transferred to a hydrothermal reactor, and a piece of FTO conductive glass is placed in the hydrothermal reactor. After sealing, the reactor is placed in a constant temperature drying oven for hydrothermal reaction. After the reaction is completed, it is naturally cooled to room temperature, and after being taken out, cleaned and dried, a nickel-manganese bimetallic hydroxide electrochromic film is obtained.

[0014] Furthermore, the FTO conductive glass is placed in the reactor with the conductive surface facing down and at an angle.

[0015] Furthermore, in step S2, the hydrothermal reaction time is 4–8 hours, and the hydrothermal reaction temperature is 120–180°C.

[0016] The second objective of this invention is to provide a nickel-manganese bimetallic hydroxide electrochromic thin film, wherein the nickel-manganese bimetallic hydroxide electrochromic thin film is directly grown on the surface of FTO conductive glass, and the electrochromic thin film has a porous structure composed of multiple nanosheets.

[0017] Furthermore, the FTO conductive glass is fluorine-doped tin dioxide FTO conductive glass.

[0018] Furthermore, the thickness of the nickel-manganese bimetallic hydroxide electrochromic film is approximately 230–480 nm.

[0019] The third objective of this invention is to provide an application of a nickel-manganese bimetallic hydroxide electrochromic film, applying the aforementioned nickel-manganese bimetallic hydroxide electrochromic film to electrochromic and related fields.

[0020] The fourth objective of this invention is to provide a method for preparing a nickel-manganese bimetallic oxide electrochromic thin film, the specific steps of which are as follows:

[0021] The nickel-manganese bimetallic hydroxide electrochromic film was obtained by high-temperature calcination.

[0022] Furthermore, the aforementioned nickel-manganese bimetallic hydroxide electrochromic film was placed in a muffle furnace and calcined at high temperature.

[0023] Furthermore, the calcination temperature is 350–500℃, and the calcination time is 0.5–4h.

[0024] The fifth objective of this invention is to provide a nickel-manganese bimetallic oxide electrochromic thin film, wherein the nickel-manganese bimetallic oxide electrochromic thin film is directly grown on the surface of FTO conductive glass, and the electrochromic thin film has a porous structure composed of multiple nanosheets.

[0025] Furthermore, the FTO conductive glass is fluorine-doped tin dioxide FTO conductive glass.

[0026] Furthermore, the thickness of the nickel-manganese bimetallic oxide electrochromic film is approximately 200–450 nm.

[0027] The sixth objective of this invention is to provide an application of a nickel-manganese bimetallic oxide electrochromic film, applying the aforementioned nickel-manganese bimetallic oxide electrochromic film to electrochromic and related fields.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. This invention enables the preparation of NiMnLDH thin films and nickel-manganese bimetallic oxide thin films on FTO conductive glass by adjusting parameters such as the composition of the hydrothermal precursor solution, the hydrothermal reaction time and temperature, and the calcination temperature and time. The surface microstructure of the NiMnLDH and nickel-manganese bimetallic oxide thin films is nanosheet-like, and the resulting films exhibit good electrochromic effects.

[0030] 2. This invention obtains a neutral-tone color-changing film by controlling reaction time, temperature, precursor solution concentration, urea content, etc., and its fading state can achieve colorless and transparent properties;

[0031] 3. The present invention prepares nickel-manganese bimetallic hydroxide and oxide thin films, wherein both Ni and Mn have variable valence states, which can realize a dual electrochromic effect, thereby overcoming the defects of limited light modulation amplitude and insignificant color change of single inorganic materials;

[0032] 4. The NiMnLDH thin film of the present invention has a large optical modulation amplitude (68%) and good energy storage performance;

[0033] 5. The preparation process of this invention is simple, requires little equipment, uses inexpensive and readily available raw materials, and has a low cost;

[0034] 6. Compared with single nickel oxide and manganese oxide, the NiMnLDH thin film and nickel-manganese bimetallic oxide thin film of the present invention have a larger light modulation amplitude in the visible light region and higher transmittance in the fading state, and can be applied to electrochromic and related fields. Attached Figure Description

[0035] Figure 1 The XRD pattern of the NiMnLDH thin film prepared in Example 1 of this invention;

[0036] Figure 2 SEM image of the NiMnLDH thin film prepared in Example 1 of this invention;

[0037] Figure 3 The XRD pattern of the Ni6MnO8 thin film prepared in Example 1 of this invention;

[0038] Figure 4 SEM image of the Ni6MnO8 thin film prepared in Example 1 of this invention;

[0039] Figure 5 Cyclic voltammetry curves of the NiMnLDH thin film prepared in Example 1 of this invention;

[0040] Figure 6 This is a diagram showing the color-changing effect of the NiMnLDH thin film prepared in Example 1 of the present invention;

[0041] Figure 7 The transmittance curve of the NiMnLDH thin film prepared in Example 1 of this invention;

[0042] Figure 8 The response time curve of the NiMnLDH thin film prepared in Example 1 of this invention;

[0043] Figure 9 The coloring efficiency curve is shown for the NiMnLDH thin film prepared in Example 1 of this invention. Detailed Implementation

[0044] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0045] One objective of this invention is to provide a method for preparing a nickel-manganese bimetallic hydroxide electrochromic thin film, the specific steps of which are as follows:

[0046] S1. Dissolve nickel source, manganese source, urea and ammonium fluoride in deionized water to obtain a hydrothermal reaction precursor solution;

[0047] S2. FTO conductive glass is added to the hydrothermal reaction precursor solution obtained in step S1, and a hydrothermal reaction is carried out to obtain a nickel-manganese bimetallic hydroxide (NiMnLDH) electrochromic film.

[0048] Further, in step S1, the nickel source is selected from nickel chloride hexahydrate, nickel acetate tetrahydrate, or nickel sulfate hexahydrate; the molar concentration of the nickel source in the hydrothermal reaction precursor solution is 0.005–0.025 mol / L.

[0049] Further, in step S1, the manganese source is selected from manganese nitrate tetrahydrate, manganese sulfate monohydrate, or manganese acetate tetrahydrate; the molar ratio of nickel to manganese in the hydrothermal reaction precursor solution is 1:5 to 5:1.

[0050] Furthermore, in step S1, the mass concentration of ammonium fluoride in the hydrothermal reaction precursor solution is 2–10 g / L.

[0051] Furthermore, in step S1, the mass concentration of urea in the hydrothermal reaction precursor solution is 2–10 g / L.

[0052] Further, in step S2, the hydrothermal reaction precursor solution obtained in step S1 is transferred to a hydrothermal reactor, and a piece of FTO conductive glass is placed in the hydrothermal reactor. After sealing, the reactor is placed in a constant temperature drying oven for hydrothermal reaction. After the reaction is completed, it is naturally cooled to room temperature, and after being taken out, cleaned and dried, a nickel-manganese bimetallic hydroxide electrochromic film is obtained.

[0053] Furthermore, the FTO conductive glass is placed in the reactor with the conductive surface facing down and at an angle.

[0054] Furthermore, in step S2, the hydrothermal reaction time is 4–8 hours, and the hydrothermal reaction temperature is 120–180°C.

[0055] The second objective of this invention is to provide a nickel-manganese bimetallic hydroxide electrochromic thin film, wherein the nickel-manganese bimetallic hydroxide electrochromic thin film is directly grown on the surface of FTO conductive glass, and the electrochromic thin film has a porous structure composed of multiple nanosheets.

[0056] Furthermore, the FTO conductive glass is fluorine-doped tin dioxide FTO conductive glass.

[0057] Furthermore, the thickness of the nickel-manganese bimetallic hydroxide electrochromic film is approximately 230–480 nm.

[0058] The third objective of this invention is to provide an application of a nickel-manganese bimetallic hydroxide electrochromic film, applying the aforementioned nickel-manganese bimetallic hydroxide electrochromic film to electrochromic and related fields.

[0059] The fourth objective of this invention is to provide a method for preparing a nickel-manganese bimetallic oxide electrochromic thin film, the specific steps of which are as follows:

[0060] The nickel-manganese bimetallic hydroxide electrochromic film was obtained by high-temperature calcination.

[0061] Furthermore, the aforementioned nickel-manganese bimetallic hydroxide electrochromic film was placed in a muffle furnace and calcined at high temperature.

[0062] Furthermore, the calcination temperature is 350–500℃, and the calcination time is 0.5–4h.

[0063] The fifth objective of this invention is to provide a nickel-manganese bimetallic oxide electrochromic thin film, wherein the nickel-manganese bimetallic oxide electrochromic thin film is directly grown on the surface of FTO conductive glass, and the electrochromic thin film has a porous structure composed of multiple nanosheets.

[0064] Furthermore, the FTO conductive glass is fluorine-doped tin dioxide FTO conductive glass.

[0065] Furthermore, the thickness of the nickel-manganese bimetallic oxide electrochromic film is approximately 200–450 nm.

[0066] The sixth objective of this invention is to provide an application of a nickel-manganese bimetallic oxide electrochromic film, applying the aforementioned nickel-manganese bimetallic oxide electrochromic film to electrochromic and related fields.

[0067] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. However, the following embodiments are not intended to limit the present invention. The amount of inorganic compound added in the following embodiments may be selected from commercially available products with similar performance. The size of the FTO conductive glass can be adjusted according to the volume of the hydrothermal reactor liner and is suitable for other conductive glass substrate materials. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention are considered equivalent substitutions and are included within the protection scope of the present invention.

[0068] Example 1

[0069] A method for preparing a nickel-manganese bimetallic hydroxide electrochromic thin film and a nickel-manganese bimetallic oxide electrochromic thin film, the specific steps of which are as follows:

[0070] First, dissolve 0.18 g of nickel chloride hexahydrate and 0.04 g of manganese sulfate monohydrate in 50 mL of deionized water and stir to obtain a clear solution. Then, add 0.19 g of ammonium fluoride and 0.20 g of urea respectively, and stir until dissolved to obtain a hydrothermal reaction precursor solution. Transfer the resulting solution to a polytetrafluoroethylene (PTFE) reactor liner, and then place a clean piece of material measuring 2.5 × 5 cm into the reactor. 2 The FTO conductive glass was tilted so that the conductive surface faced down. The reactor was sealed and placed in a constant temperature drying oven. It was reacted at 160°C for 4 hours and then naturally cooled to room temperature.

[0071] The FTO conductive glass was removed from the reactor, rinsed with deionized water and anhydrous ethanol, and then dried to obtain the NiMnLDH thin film with the properties to be tested. This film was then placed in a muffle furnace and calcined at 350°C for 2 hours to obtain a nickel-manganese bimetallic oxide thin film.

[0072] The XRD pattern of the NiMnLDH thin film prepared in Example 1 is as follows: Figure 1 As shown in the figure, the diffraction peaks at 2θ = 23° and 60.1° correspond to the characteristic diffraction peaks of the NiMnLDH standard card, indicating that the NiMnLDH thin film was successfully prepared by a one-step hydrothermal method. Figure 2The image shows a SEM image of the film. It can be seen from the image that the film is composed of NiMnLDH with a nanosheet structure and has a porous structure. This structure is conducive to ion implantation and extraction, and is suitable for electrochromic layers, supercapacitors and other fields. Figure 3 The image shows the XRD pattern of the calcined film. A significant change in the diffraction peaks can be observed, with a strong peak at 2θ = 38.8° corresponding to Ni6MnO8. This indicates that the film transformed from NiMnLDH to a nickel-manganese bimetallic oxide after calcination. However, its morphology remained largely unchanged, still consisting of nanosheets. Figure 4 As shown.

[0073] The NiMnLDH thin film obtained in Example 1 was subjected to 1 mol·L⁻¹ -1 The performance was tested in a KOH electrolyte solution using a three-electrode system, in which the prepared thin film was the working electrode, the platinum sheet was the counter electrode, and the Hg / HgO electrode was the reference electrode. Figure 5 This is a cyclic voltammetry (CV) curve. 1V is chosen as the coloring voltage, and -1.2V as the fading voltage, as follows: Figure 6 As shown, the film can vary between light brown and dark brown. The transmittance curves of its colored and faded states were measured using an electrochemical workstation connected to a UV spectrophotometer in the wavelength range of 400–1100 nm. The results are as follows. Figure 7 As shown, the transmittance change is greatest at 550 nm, approximately 68.0%, indicating that the light modulation amplitude reaches its maximum at 550 nm. Therefore, the electrochromic response time curve of the thin film was further tested at 550 nm, and the test results are shown below. Figure 8 As shown. Taking the time required to reach 90% of the change in light modulation amplitude as the response time, the coloring time of the NiMnLDH film was calculated to be approximately 14 s, and the fading time was approximately 26 s. Figure 9 The curve showing the optical density versus charge density of the NiMnLDH thin film is shown. The calculated coloring efficiency of the NiMnLDH thin film is 56.2 cm⁻¹. 2 / C.

[0074] The performance tests of the nickel-manganese bimetallic oxide film obtained in Example 1 were conducted as described above, and the results are shown in Table 2. Compared with the NiMnLDH film, the light modulation amplitude of the nickel-manganese bimetallic oxide film is only 30.0%, and the coloring efficiency is also significantly reduced. This is mainly because the nickel-manganese bimetallic oxide film is difficult to fade and has a low transmittance in the faded state. Due to the indistinct color change, the time required for color change is shorter, thus the response time is significantly shortened.

[0075] Example 2

[0076] First, dissolve 0.18 g of nickel chloride hexahydrate and 0.18 g of manganese nitrate tetrahydrate in 50 mL of deionized water and stir to obtain a clear solution. Then, add 0.10 g of ammonium fluoride and 0.10 g of urea respectively, and stir until dissolved to obtain a hydrothermal reaction precursor solution. Transfer the resulting solution to a polytetrafluoroethylene (PTFE) reactor liner, and then place a clean piece of material measuring 2.5 × 5 cm into the reactor. 2 The FTO conductive glass was tilted so that the conductive surface faced down. The reactor was sealed and placed in a constant temperature drying oven. It was reacted at 140°C for 6 hours and then naturally cooled to room temperature.

[0077] The FTO conductive glass was removed from the reactor, rinsed with deionized water and anhydrous ethanol, and then dried to obtain the NiMnLDH thin film with the properties to be tested. This film was then placed in a muffle furnace and calcined at 350°C for 4 hours to obtain a nickel-manganese bimetallic oxide thin film.

[0078] The performance tests of the NiMnLDH film and the nickel-manganese bimetallic oxide film obtained in Example 2 were the same as those in Example 1, and the test results are shown in Tables 1 and 2. Table 1 shows that the light modulation amplitude and coloring efficiency of the NiMnLDH film in Example 2 are significantly lower than those of the NiMnLDH film in Example 1, but the response time is shorter. This may be due to the lower hydrothermal reaction temperature and reduced urea addition, leading to incomplete reaction and a thinner film. Table 2 shows that the light modulation amplitude, coloring efficiency, and coloring time of the nickel-manganese bimetallic oxide film obtained in Example 2 are very close to those in Example 1, but the fading time is increased. This may be due to the extended calcination time to 4 hours, resulting in a denser film and making it more difficult for intercalated ions to intercalate and deintercalate.

[0079] Example 3

[0080] First, dissolve 0.06 g of nickel acetate tetrahydrate and 0.30 g of manganese acetate tetrahydrate in 50 mL of deionized water and stir to obtain a clear solution. Then, add 0.48 g of ammonium fluoride and 0.50 g of urea respectively, and stir until dissolved to obtain a hydrothermal reaction precursor solution. Transfer the resulting solution to a polytetrafluoroethylene (PTFE) reactor liner, and then place a clean piece of material measuring 2.5 × 5 cm into the reactor. 2 The FTO conductive glass was tilted so that the conductive surface faced down. The reactor was sealed and placed in a constant temperature drying oven. It was reacted at 180°C for 2 hours and then naturally cooled to room temperature.

[0081] The FTO conductive glass was removed from the reactor, rinsed with deionized water and anhydrous ethanol, and then dried to obtain the NiMnLDH thin film with the properties to be tested. This film was then placed in a muffle furnace and calcined at 450°C for 1 hour to obtain a nickel-manganese bimetallic oxide thin film.

[0082] The performance tests of the NiMnLDH film and the nickel-manganese bimetallic oxide film obtained in Example 3 were the same as those in Example 1, and the test results are shown in Tables 1 and 2. As can be seen from Table 1, the light modulation amplitude and coloring efficiency of the NiMnLDH film obtained in Example 3 are significantly lower than those of the NiMnLDH films in Examples 1, 2, and 4, but the response time is the shortest. This may be because the color change of the NiMnLDH film mainly depends on the change in the Ni valence state, while the concentration of the nickel source in Example 3 is relatively low. As can be seen from Table 2, the light modulation amplitude and coloring efficiency of the nickel-manganese bimetallic oxide film obtained in Example 3 are also significantly lower than those of the other examples, for the same reasons as above.

[0083] Example 4

[0084] First, dissolve 0.33 g of nickel sulfate hexahydrate and 0.04 g of manganese sulfate monohydrate in 50 mL of deionized water and stir to obtain a clear solution. Then, add 0.38 g of ammonium fluoride and 0.40 g of urea respectively, and stir until dissolved to obtain a hydrothermal reaction precursor solution. Transfer the resulting solution to a polytetrafluoroethylene (PTFE) reactor liner, and then place a clean piece of material measuring 2.5 × 5 cm into the reactor. 2 The FTO conductive glass was tilted so that the conductive surface faced down. The reactor was sealed and placed in a constant temperature drying oven. It was reacted at 120°C for 8 hours and then naturally cooled to room temperature.

[0085] The FTO conductive glass was removed from the reactor, rinsed with deionized water and anhydrous ethanol, and then dried to obtain the NiMnLDH thin film with the properties to be tested. This film was then placed in a muffle furnace and calcined at 500°C for 0.5 h to obtain a nickel-manganese bimetallic oxide thin film.

[0086] The performance tests of the NiMnLDH film and the nickel-manganese bimetallic oxide film obtained in Example 4 were the same as those in Example 1, and the test results are shown in Tables 1 and 2. Table 1 shows that the light modulation amplitude and coloring efficiency of the NiMnLDH film in Example 4 are similar to those in Example 2, but both are significantly smaller than those of the NiMnLDH film in Example 1, and the response time is shorter than that of Example 2. This may be because the hydrothermal reaction temperature in Example 4 is the lowest, leading to incomplete reaction and a thinner film. Table 2 shows that the light modulation amplitude, coloring efficiency, and response time of the nickel-manganese bimetallic oxide film obtained in Example 4 are very close to those in Example 2.

[0087] Table 1 Comparison of the electrochromic properties of NiMnLDH thin films prepared in each example

[0088]

[0089]

[0090] Table 2 Comparison of the electrochromic properties of nickel-manganese bimetallic oxide films prepared in each example

[0091]

[0092] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for preparing a nickel-manganese bimetallic hydroxide electrochromic thin film, characterized in that, The specific steps are as follows: S1, dissolving a nickel source, a manganese source, urea and ammonium fluoride in deionized water to obtain a hydrothermal reaction precursor solution; S2, transferring the hydrothermal reaction precursor solution obtained in step S1 into a hydrothermal reaction kettle, placing a piece of FTO conductive glass into the hydrothermal reaction kettle, sealing the hydrothermal reaction kettle, and then placing the reaction kettle into a constant temperature drying box for hydrothermal reaction, after the reaction is completed, naturally cooling to room temperature, and then taking out, washing and drying to obtain a nickel-manganese bimetallic hydroxide electrochromic film, wherein the nickel-manganese bimetallic hydroxide electrochromic film is directly grown on the surface of the FTO conductive glass, the structure of the electrochromic film is a porous structure composed of a plurality of nanosheets, and the light modulation amplitude of the nickel-manganese bimetallic hydroxide electrochromic film at a wavelength of 550 nm is 68%; In step S1, the nickel source is selected from nickel chloride hexahydrate, nickel acetate tetrahydrate or nickel sulfate hexahydrate; the molar concentration of the nickel source in the hydrothermal reaction precursor solution is 0.005-0.025 mol / L, the manganese source is selected from manganese nitrate tetrahydrate, manganese sulfate monohydrate or manganese acetate tetrahydrate; and the molar ratio of nickel to manganese in the hydrothermal reaction precursor solution is 1:5-5:1, In step S2, the FTO conductive glass is placed in the reaction kettle in a manner that the conductive surface faces downward and is inclined, the hydrothermal reaction time is 4-8 h, and the hydrothermal reaction temperature is 120-180℃.

2. The preparation method of the nickel-manganese bimetallic hydroxide electrochromic film according to claim 1, characterized in that, In step S1, the mass concentration of ammonium fluoride in the hydrothermal reaction precursor solution is 2-10 g / L, the mass concentration of urea in the hydrothermal reaction precursor solution is 2-10 g / L.

3. A nickel-manganese double metal hydroxide electrochromic thin film, characterized in that, The nickel-manganese bimetallic hydroxide electrochromic film Prepared by the preparation method of claim 1 or claim 2.

4. The nickel-manganese bimetallic hydroxide electrochromic thin film according to claim 3, characterized in that, The FTO conductive glass is fluorine-doped tin dioxide FTO conductive glass; The thickness of the nickel-manganese bimetallic hydroxide electrochromic film is 230-480 nm.

5. Use of a nickel-manganese double metal hydroxide electrochromic thin film, characterized in that, The nickel-manganese bimetallic hydroxide electrochromic film of claim 3 or claim 4 is applied to the field of electrochromism and related fields.

6. A method for preparing a nickel-manganese bimetallic oxide electrochromic thin film, characterized in that, The specific steps are as follows: The nickel-manganese bimetallic hydroxide electrochromic film prepared by the preparation method of claim 1 or claim 2 is calcined at high temperature to obtain a nickel-manganese bimetallic oxide electrochromic film.

7. The method according to claim 6, wherein the method is characterized by, The nickel-manganese bimetallic hydroxide electrochromic film is placed in a muffle furnace for high-temperature calcination; The calcination temperature is 350-500℃, and the calcination time is 0.5-4 h.

8. A nickel-manganese bimetallic oxide electrochromic thin film, characterized in that, The nickel-manganese bimetallic oxide electrochromic film prepared by the preparation method of claim 6 or claim 7 is directly grown on the surface of the FTO conductive glass, and the structure of the electrochromic film is a porous structure composed of a plurality of nanosheets.

9. The nickel-manganese bimetallic oxide electrochromic thin film according to claim 8, characterized in that, The FTO conductive glass is fluorine-doped tin dioxide FTO conductive glass; The thickness of the nickel-manganese bimetallic oxide electrochromic film is 200-450 nm.

10. Use of a nickel-manganese bimetallic oxide electrochromic thin film, characterized in that, The nickel-manganese bimetallic oxide electrochromic film of claim 8 or claim 9 is applied to the field of electrochromism and related fields.

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