Electrochromic battery as well as preparation method and use method thereof

Abstract

The invention discloses an electrochromic battery and a preparation method and a use method thereof, the electrochromic battery comprises a transparent conductive cathode, an anode and an electrolyte arranged between the transparent conductive cathode and the anode, the electrolyte comprises an electrolyte and an electrochromic material, the electrochromic material is molybdenum oxide, and the electrolyte and the electrochromic material are electrically conductive. The chemical formula of molybdenum oxide is MoOx, x is more than 2 and less than 3, and the anode material is aluminum. The electrochromic battery provided by the invention presents continuous and reversible color transition, and in the discharging process, the system is changed from fully charged yellow to green with reduced electric quantity and then to exhausted blue. And moreover, hydrogen peroxide is added in the use process, so that the electrochromic battery disclosed by the invention can realize rapid energy charging and bleaching. Specifically, hydrogen peroxide is added into the blue electrolyte of which the electric quantity is exhausted, so that the open-circuit voltage can be quickly recovered, and meanwhile, the blue electrolyte is changed into a yellow state, and good recyclability is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of new materials, and in particular to an electrochromic battery and a preparation method and a use method thereof. Background Art

[0002] As attention to energy consumption and sustainable development issues increases, research on innovative technologies for energy conservation and enhanced energy utilization is being actively promoted. Multifunctional electrochemical devices based on metal ion insertion and deintercalation stimulation have broad application prospects in future energy storage and conversion systems. The charging and discharging process of the battery is accompanied by electrochemical redox reactions or the insertion / dissolution of ions, a phenomenon similar to the reversible color change caused by the insertion / extraction of ions under external electrical stimulation in electrochromic devices. As an emerging intelligent coloring energy storage system that integrates the above two methods, electrochromic batteries monitor electrochemical charging and discharging reactions in real time through color conversion visualization, becoming a highly sought-after new device.

[0003] Although electrochromic cells have the ability to continuously and reversibly change their optical and electrical properties under the influence of voltage, existing electrochromic cells require external voltage triggers during the color change and fading process, resulting in reduced energy efficiency. It is still a challenge for existing electrochromic cells to achieve fully controllable and efficient self-coloration and self-bleaching processes.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide an electrochromic battery and a preparation method and a use method thereof, aiming to solve the problems of slow self-charging process and limited color change of the existing electrochromic batteries.

[0006] The technical solution of the present invention is as follows:

[0007] In a first aspect of the present invention, an electrochromic battery is provided, the electrochromic battery comprising a transparent conductive cathode, an anode and an electrolyte disposed between the transparent conductive cathode and the anode, the electrolyte comprising an electrolyte and an electrochromic material, the electrochromic material being molybdenum oxide, the chemical formula of the molybdenum oxide being MoO x , 2<x<3, the anode material is aluminum.

[0008] Preferably, the electrochromic material is molybdenum oxide nanosheets.

[0009] Preferably, the electrolyte is one or both of N-methyl-2-pyrrolidone and N-butylpyrrolidone.

[0010] Preferably, the electrolyte also includes one or more of phosphoric acid, water and hydrochloric acid.

[0011] Preferably, the electrolyte also includes one or more of aluminum chloride, aluminum nitrate and aluminum sulfate.

[0012] Preferably, the transparent conductive cathode material is selected from one of conductive glass indium tin oxide, fluorine-doped tin dioxide, and indium-doped zinc oxide.

[0013] A second aspect of the present invention provides a method for preparing the above-mentioned electrochromic battery, the method comprising the following steps:

[0014] dissolving molybdenum oxide powder and electrolyte in water and heating the mixture to obtain an electrolyte solution containing molybdenum oxide;

[0015] The electrolyte containing molybdenum oxide is assembled with a transparent conductive cathode and an anode to obtain the electrochromic battery.

[0016] Preferably, the electrolyte also includes one or more of phosphoric acid, water, and hydrochloric acid; the electrolyte also includes one or more of aluminum chloride, aluminum nitrate, and aluminum sulfate.

[0017] Preferably, in the electrolyte containing molybdenum oxide, the molar ratio of molybdenum oxide powder, water and electrolyte is (0.62-3.1):25:14.98.

[0018] A third aspect of the present invention provides a method for using the electrochromic battery, the method comprising the steps of: adding hydrogen peroxide to the electrolyte to complete charging of the electrochromic battery.

[0019] Beneficial effects: The present invention provides an electrochromic battery and a preparation method and a use method thereof. The electrochromic battery provided by the present invention exhibits a continuous and reversible color transition. During the discharge process, the system changes from fully charged yellow to reduced power green and then to exhausted blue. And by adding hydrogen peroxide during use, the electrochromic battery of the present invention can achieve rapid charging and bleaching. Specifically, adding hydrogen peroxide to the exhausted blue electrolyte can quickly restore the open circuit voltage and turn it into a yellow state, which has good cyclability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of an electrochromic battery prepared according to an embodiment of the present invention.

[0021] Figure 2 This is a real picture of the color change of the electrochromic battery prepared in an embodiment of the present invention during three charge and discharge processes and the dilution of part of the electrolyte by 10 times.

[0022] Figure 3 This is a graph showing the voltage variation over time during three charge and discharge processes of the electrochromic battery prepared in an embodiment of the present invention.

[0023] Figure 4 This is a graph showing the change in absorbance of the electrolyte at 700 nm over time during three charge and discharge processes of the electrochromic battery prepared in an embodiment of the present invention.

[0024] Figure 5 This is a diagram showing the actual voltage measurement of the molybdenum oxide-aluminum hydrogel battery provided by the present invention.

[0025] Figure 6 The figures are actual pictures of the molybdenum oxide-aluminum hydrogel battery provided by the present invention after being in contact with the aluminum sheet for 0 minutes and 5 minutes. DETAILED DESCRIPTION

[0026] The present invention provides an electrochromic battery and a preparation method and a use method thereof. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0027] Electrochromic batteries are an emerging smart color energy storage system that can visualize electrochemical charge and discharge reactions in real time through color conversion, making them a highly sought-after new device. However, they are still hampered by their slow self-charging process and limited color change.

[0028] Based on this, an embodiment of the present invention provides an electrochromic battery, the electrochromic battery comprising a transparent conductive cathode, an anode and an electrolyte disposed between the transparent conductive cathode and the anode, the electrolyte comprising an electrolyte and an electrochromic material, the electrochromic material being molybdenum oxide, the chemical formula of the molybdenum oxide being MoO x , 2<x<3, the anode material is aluminum.

[0029] The transparent conductive cathode and the molybdenum oxide in the electrolyte form a closed loop, in which the aluminum anode loses electrons, which are easily captured by the molybdenum oxide in the electrolyte. Due to the redox potential difference between the aluminum anode and the molybdenum oxide, the electrochromic battery has an initial potential of 1.14V and can power a small electronic watch. During the discharge process from 1.14V to 0.9V, the molybdenum oxide in the electrolyte captures electrons, achieving a multi-color change from high-charge yellow to green to depleted blue (Mo 6+ →Mo 5+ ).

[0030] The multicolor color change based on molybdenum oxide-aluminum battery provided by the embodiment of the present invention overcomes the obstacles of slow self-charging process and limited color change of traditional electrochromic batteries. At the same time, in the field of molybdenum oxide-aluminum for both color change and energy storage, it solves the problem that traditional electrochromic materials need an external power supply to change color.

[0031] In some embodiments, the electrochromic material is molybdenum oxide nanosheets.

[0032] The molybdenum oxide nanomaterial used in the embodiment of the present invention is a molybdenum oxide nanosheet obtained by hydrothermal exfoliation of molybdenum oxide powder.

[0033] In some embodiments, the electrolyte is one or both of N-methyl-2-pyrrolidone and N-butylpyrrolidone.

[0034] In some embodiments, the electrolyte further includes one or more of phosphoric acid, water, and hydrochloric acid.

[0035] In some embodiments, the electrolyte further includes one or more of aluminum chloride, aluminum nitrate, and aluminum sulfate.

[0036] The addition of phosphoric acid and aluminum chloride can increase the conductivity of the electrolyte and also provide H + 、Al 3+ , MoO2 nanosheets are two-dimensional layered structures. + 、Al 3+ Insertion between molybdenum oxide layers causes a change in the valence state of molybdenum, resulting in a color change in the battery.

[0037] It also provides multiple ions (H + 、Al 3+ ) insert electrodes to improve electrochromic efficiency and energy storage capacity.

[0038] In some embodiments, the transparent conductive cathode material is selected from one of conductive glass indium tin oxide, fluorine-doped tin dioxide, and indium-doped zinc oxide.

[0039] The present invention provides a method for preparing the electrochromic battery, which comprises the following steps:

[0040] dissolving molybdenum oxide powder and electrolyte in water and heating the mixture to obtain an electrolyte solution containing molybdenum oxide;

[0041] The electrolyte containing molybdenum oxide is assembled with a transparent conductive cathode and an anode to obtain the electrochromic battery.

[0042] In the embodiment of the present invention, molybdenum oxide powder is exfoliated by a hydrothermal method to obtain molybdenum oxide nanosheets.

[0043] In some embodiments, the electrolyte further includes one or more of phosphoric acid, water, and hydrochloric acid; the electrolyte further includes one or more of aluminum chloride, aluminum nitrate, and aluminum sulfate.

[0044] In some embodiments, in the electrolyte containing molybdenum oxide, the molar ratio of molybdenum oxide powder, water, and electrolyte is (0.62-3.1):25:14.98.

[0045] When H + 、Al 3+ When the content is low, the electrolyte conductivity is low, the battery voltage is low, and it is difficult to achieve the function of supplying energy to the external load. At the same time, the battery electrochromic efficiency is low and the color changes slowly. + 、Al 3+ When the content is high, the molybdenum oxide-aluminum reaction in the electrolyte is easily replaced by the competitive reaction of aluminum electrolysis of water, making it impossible for molybdenum oxide to achieve the expected color change effect.

[0046] In some preferred embodiments, in the electrolyte containing molybdenum oxide, the molar ratio of molybdenum oxide powder, water, and electrolyte is 3.1:25:14.98.

[0047] An embodiment of the present invention provides a method for using the electrochromic battery, which includes the steps of: adding hydrogen peroxide to the electrolyte to complete charging of the electrochromic battery.

[0048] The electrochromic battery of the embodiment of the present invention integrates hydrogen peroxide power generation and energy storage into the battery structure. When the electrolyte turns blue, the potential difference gradually decreases. At this time, hydrogen peroxide is added to the electrolyte, and the electrochromic battery is self-charged to 1.1 V through the redox reaction with molybdenum oxide. The self-charging process is completed in about 30 minutes, and the color of the solution quickly changes to yellow.

[0049] The electrochromic battery provided in this embodiment can complete three charge-discharge and color change cycles, and the amount of electricity and the color change are always closely related during the cycle.

[0050] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, and are only for illustrating the present invention but not limiting the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0051] Example

[0052] The preparation of the electrochromic cell comprises the following steps:

[0053] 0.15 g of molybdenum oxide powder, 5 mL of water and 5 mL of N-methyl-2-pyrrolidone (NMP) were mixed to obtain a mixed solution, the mixed solution was stirred and heated in a reaction kettle at 120° C. for 150 minutes, and then centrifuged at 1000 rpm for 10 minutes, and the supernatant was taken to obtain an electrolyte containing molybdenum oxide;

[0054] The electrolyte containing molybdenum oxide, phosphoric acid and aluminum oxide solution (1.58 mol / L) were mixed in a volume ratio of 9 mL: 0.3 mL: 0.64 mL to obtain a mixed electrolyte containing molybdenum oxide, phosphoric acid and aluminum oxide, and the mixed electrolyte was assembled with an aluminum sheet anode and a conductive glass indium tin oxide (ITO) cathode to obtain an electrochromic battery, as shown in the schematic diagram. Figure 1 shown.

[0055] Figure 2 The color change of the electrochromic battery prepared in the embodiment during three charge and discharge processes and the physical picture of part of the electrolyte diluted ten times. It can be seen from the figure that the solution is in a yellow state after the circuit is connected, and can power a small electronic watch. As the battery discharges, the molybdenum oxide nanosheets in the electrolyte gain electrons, and the Mo ions change from +6 valence to +5 valence. The electrolyte gradually changes from yellow to green and finally to blue. When the electrolyte is in a blue state, the power of the electrochromic battery drops significantly, and the electronic watch display is blurred. After the first addition of hydrogen peroxide to charge, the electrolyte quickly turns light green, and the electronic meter number is clearly displayed. After adding hydrogen peroxide for about an hour, the solution still maintains a full yellow state. The battery charge and discharge cycles show the same color change three times, indicating its stable multi-color electrochromic performance.

[0056] Figure 3 The voltage of the electrochromic battery prepared in the embodiment changes with time during the three charge and discharge processes. It can be seen from the figure that the initial open circuit voltage of the electrochromic battery is 1.14V. As the battery discharges, the voltage drops to 0.91V in about 3 hours. At this time, hydrogen peroxide is added to the electrolyte, and the voltage rises rapidly, and recovers to 1.1V in about 30 minutes. And because hydrogen peroxide exists in the electrolyte, it continuously reacts with the MoO2 reduced in the battery reaction process. x The battery maintained 1.1V and continued to discharge for 90 minutes, which increased the discharge time of the electrochromic battery. Adding an equal amount of hydrogen peroxide to the battery electrolyte that was continuously discharged to 0.9V still enabled rapid charging.

[0057] MoO2 nanosheets have strong localized surface plasmon resonance absorption, which is manifested in the Mo 6+ Restore to Mo 5+During the process of charging and discharging, the absorption peak at 700nm gradually increases, and the corresponding color changes from yellow to green to blue. The absorbance at 700nm changes with time when the electrolyte is diluted 40 times during the three charge and discharge processes of the electrochromic battery prepared in the embodiment of the present invention as shown in FIG. Figure 4 As shown in the figure, during the discharge process of the electrochromic battery, the absorbance gradually increases, and after adding hydrogen peroxide, the absorbance rapidly decreases to a state close to the initial state. Battery absorbance change over time ( Figure 4 ) and voltage-time diagram ( Figure 3 ), indicating the feasibility of characterizing battery power by color change.

[0058] In addition, in order to further expand the application scope of the electrochromic battery prepared in this embodiment, the electrolyte is combined with polyvinyl alcohol hydrogel, and the prepared molybdenum oxide-aluminum hydrogel battery also has a voltage change corresponding to the color change. After the molybdenum oxide hydrogel is combined with the aluminum sheet, it can provide a voltage of about 1V. After five minutes, the yellow hydrogel gradually turns green, and the hydrogel in contact with the aluminum sheet has quickly turned blue. (See Figure 5 : Voltage measurement diagram of molybdenum oxide-aluminum hydrogel battery, Figure 6 : Actual photos of molybdenum oxide-aluminum hydrogel battery in contact with aluminum sheet for 0 minutes and 5 minutes)

[0059] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. An electrochromic battery, characterized in that: The electrochromic battery comprises a transparent conductive cathode, an anode and an electrolyte disposed between the transparent conductive cathode and the anode, wherein the electrolyte comprises an electrolyte and an electrochromic material, wherein the electrochromic material is molybdenum oxide, and the chemical formula of the molybdenum oxide is MoO x , 2<x<3, the anode material is aluminum.

2. The electrochromic battery according to claim 1, characterized in that: The electrochromic material is molybdenum oxide nanosheets.

3. The electrochromic battery according to claim 1, characterized in that: The electrolyte is one or both of N-methyl-2-pyrrolidone and N-butylpyrrolidone.

4. The electrochromic battery according to claim 1, characterized in that: The electrolyte also includes one or more of phosphoric acid, water and hydrochloric acid.

5. The electrochromic battery according to claim 1, characterized in that: The electrolyte also includes one or more of aluminum chloride, aluminum nitrate, and aluminum sulfate.

6. The electrochromic battery according to claim 1, characterized in that: The transparent conductive cathode material is selected from one of conductive glass indium tin oxide, fluorine-doped tin dioxide, and indium-doped zinc oxide.

7. A method for preparing the electrochromic battery according to claim 1, characterized in that: The preparation method comprises the following steps: dissolving molybdenum oxide powder and electrolyte in water and heating the mixture to obtain an electrolyte containing molybdenum oxide; The electrolyte containing molybdenum oxide is assembled with a transparent conductive cathode and an anode to obtain the electrochromic battery.

8. The method for preparing an electrochromic battery according to claim 7, characterized in that: The electrolyte also includes one or more of phosphoric acid, water, and hydrochloric acid; the electrolyte also includes one or more of aluminum chloride, aluminum nitrate, and aluminum sulfate.

9. The method for preparing an electrochromic battery according to claim 8, characterized in that: In the electrolyte containing molybdenum oxide, the molar ratio of molybdenum oxide powder, water and electrolyte is (0.62-3.1):25:14.

98.

10. A method for using the electrochromic battery according to claim 1, characterized in that: The method of use comprises the steps of: adding hydrogen peroxide to the electrolyte to complete the charging of the electrochromic battery.

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