All-solid-state electrochemical actuator and preparation method thereof

Abstract

The present invention discloses an all-solid-state electrochemical actuator and a preparation method thereof, which are used to solve the technical problems such as the large self-weight of the electrochemical actuator working in a liquid environment and the electrolyte leakage and evaporation of the electrochemical actuator working in a quasi-solid-state environment. An all-solid-state electrochemical reaction system is realized by preparing a driving material and a polyvinyl alcohol-sulfuric acid gel, and the assembly of the actuator is realized based on the interlayer van der Waals force formed during the pulsed laser deposition process and the super strong adhesiveness of the polyvinyl alcohol-sulfuric acid gel itself. The present invention proposes an all-solid-state electrochemical actuator that does not need to be immersed in electrolyte before use and does not need to add electrolyte during use, enriches the electrochemical driving technology, and broadens the development prospects of electrochemical actuators in research fields such as artificial muscle fibers, micro medical devices, and intelligent robots.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical drive, and particularly relates to an all-solid-state electrochemical actuator and a preparation method thereof. Background Art

[0002] In recent years, electrochemical actuators have been widely used in intelligent traps and artificial muscle fibers because they have the lowest driving voltage and the smallest energy consumption among electro-driven actuators. However, most of the existing electrochemical actuators work in a liquid environment or a quasi-solid-state environment. Among them, the self-weight of the entire electrochemical reaction system required for the electrochemical actuator working in the liquid environment is relatively large and the application range is limited; the electrochemical actuator working in the quasi-solid-state environment usually has leakage and evaporation of the electrolyte, greatly reducing its cycle durability and stability. Therefore, it is necessary to develop an all-solid-state electrochemical actuator to promote the further development and practical application of electrochemical drive technology. Summary of the Invention

[0003] The purpose of the present invention is to provide an all-solid-state electrochemical actuator and a preparation method thereof to solve the technical problem that the electrochemical actuator working in the liquid / quasi-solid-state environment is limited in application described in the background art.

[0004] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0005] An all-solid-state electrochemical actuator is successively combined by a metal foil, a driving material, an intermediate polyvinyl alcohol-sulfuric acid gel solid electrolyte, a platinum mesh electrode, and an upper polyvinyl alcohol-sulfuric acid gel solid electrolyte. Among them, the intermediate polyvinyl alcohol-sulfuric acid gel solid electrolyte and the upper polyvinyl alcohol-sulfuric acid gel solid electrolyte are combined with adjacent layers through their own strong adhesiveness.

[0006] Further, it includes a metal foil with a thickness of 1-5 μm, such as: red gold foil, silver foil, copper foil, aluminum foil, and tungsten foil.

[0007] Further, it includes a driving material with a thickness of 1-7.5 μm, such as: black phosphorus, apatite, metal-organic framework compound, transition metal dichalcogenide (including molybdenum disulfide, tungsten disulfide, molybdenum diselenide, molybdenum ditelluride, tungsten diselenide), carbon nanomaterial, metal carbon / nitride MXene.

[0008] Further, the metal foil and the driving material are tightly combined through the van der Waals force formed during the pulsed laser deposition process, and the thickness ratio of the driving material to the metal foil is (1-1.5):1.

[0009] Furthermore, the intermediate polyvinyl alcohol-sulfuric acid gel solid electrolyte and the upper polyvinyl alcohol-sulfuric acid gel solid electrolyte with a thickness of 0.1-0.5 μm are combined with adjacent layers through their own super strong adhesiveness.

[0010] In the preparation method of the all-solid-state electrochemical actuator, concentrated sulfuric acid with a mass fraction of 98% and deionized water are stirred for 5-10 minutes at a mass ratio of 1:1 to obtain a mixed solution. Subsequently, polyvinyl alcohol powders of type 1788, 1799, 2488, or 2699 with a total mass equal to that of concentrated sulfuric acid or deionized water are added in 2-5 portions to the mixed solution, and magnetically stirred at 80-100 °C for 2-4 hours until the mixture changes from a turbid state to a clear and transparent state and forms a gel. Then, it is placed in a drying oven at 75-85 °C and left standing for 3-5 hours to remove the bubbles in the gel; Subsequently, in a vacuum environment of 1×10 -8 ~9×10 - 7 Torr, the driving material is grown on the metal foil by pulsed laser deposition. The thickness ratio of the driving material to the metal foil is (1-1.5):1. Using a spin coater, the gel standing by is spin-coated on the driving material at a speed of 5000-10000 revolutions per minute within 2-4 minutes to form an intermediate polyvinyl alcohol-sulfuric acid gel solid electrolyte with a thickness of 0.1-0.5 μm. Subsequently, a platinum mesh electrode is attached to the intermediate polyvinyl alcohol-sulfuric acid gel solid electrolyte, and the gel standing by is spin-coated on the platinum mesh electrode again at the same speed and for the same time to form an upper polyvinyl alcohol-sulfuric acid gel solid electrolyte. The obtained all-solid-state electrochemical actuator is left standing in an environment of 20-25 °C for 20-24 hours.

[0011] The present invention proposes an all-solid-state electrochemical actuator that does not require soaking in electrolyte before use and does not require adding electrolyte during use, enriching the electrochemical drive technology and broadening the development prospects of electrochemical actuators in research fields such as artificial muscle fibers, micro medical devices, and intelligent robots. Compared with the prior art, the advantages of the present invention include:

[0012] (1) It can achieve the driving behavior in an all-solid-state electrochemical reaction system, thus solving technical problems such as the large self-weight of traditional electrochemical actuators, the decline of driving performance caused by electrolyte leakage and evaporation, and further broadening the application prospects of electrochemical drive technology;

[0013] (2) This method has simple process, high cycle stability, strong durability and low cost of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic structural diagram of the all-solid-state electrochemical actuator;

[0015] Figure 2 Scanning electron microscope image of the interface between the driving material (molybdenum disulfide) and polyvinyl alcohol-sulfuric acid gel;

[0016] Figure 3 Diagram showing the cuttability and flexibility of the polyvinyl alcohol-sulfuric acid gel solid electrolyte;

[0017] Figure 4 Diagram showing the tensile test results of the polyvinyl alcohol-sulfuric acid gel solid electrolyte;

[0018] Figure 5 Diagram showing the variation law of the adhesion of the polyvinyl alcohol-sulfuric acid gel solid electrolyte with temperature;

[0019] Figure 6 Diagram showing the variation law of the polyvinyl alcohol-sulfuric acid gel solid electrolyte with storage time at different storage temperatures;

[0020] Figure 7 Diagram showing the variation law of the driving displacement of the all-solid-state electrochemical actuator with the working voltage. Detailed implementation mode

[0021] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. Here, the schematic embodiments of the present invention and the description are used to explain the present invention, but do not limit the present invention.

[0022] Example 1:

[0023] A mixed solution was obtained by stirring concentrated sulfuric acid with a mass fraction of 98% and deionized water at a mass ratio of 1:1 for 5 minutes. Subsequently, polyvinyl alcohol powder of type 2699 with a total mass equal to that of concentrated sulfuric acid or deionized water was added in 5 portions to the mixed solution, and magnetically stirred at 100 °C for 4 hours at a constant speed until the mixture changed from a turbid state to clear and transparent to form a gel. The gel was placed in an oven at 85 °C and left standing for 5 hours to remove the bubbles in the gel. Subsequently, molybdenum disulfide was grown on an aluminum foil by pulsed laser deposition in a vacuum environment of 9×10 -7 Torr, and the thickness ratio of molybdenum disulfide to the aluminum foil was 1:1. As Figure 1 shown, the gel standing by was spin-coated on the driving material at a speed of 10,000 revolutions per minute within 4 minutes using a spin coater to form an intermediate polyvinyl alcohol-sulfuric acid gel solid electrolyte with a thickness of 0.5 μm. Subsequently, a platinum mesh electrode was attached to the intermediate polyvinyl alcohol-sulfuric acid gel solid electrolyte, and the gel standing by was again spin-coated on the platinum mesh electrode at the same speed and for the same time using a spin coater to form an upper polyvinyl alcohol-sulfuric acid gel solid electrolyte. The obtained all-solid-state electrochemical actuator was left standing in an environment at 25 °C for 24 hours.

[0024] The scanning electron microscope image at the interface of molybdenum disulfide and polyvinyl alcohol-sulfuric acid gel is as follows Figure 2 shown. It can be seen that the gel layer and molybdenum disulfide are closely attached, thus ensuring a fast and stable electrochemical reaction system.

[0025] Example 2:

[0026] A mixed solution was obtained by stirring concentrated sulfuric acid with a mass fraction of 98% and deionized water at a mass ratio of 1:1 for 10 minutes. Subsequently, polyvinyl alcohol powder of type 1788 with a total mass equal to that of concentrated sulfuric acid or deionized water was added in two portions to the mixed solution, and magnetically stirred at 80 °C for 2 hours at a constant speed until the mixture changed from a turbid state to clear and transparent to form a gel. Then it was placed in a drying oven at 75 °C and left standing for 3 hours to remove the bubbles in the gel.

[0027] As Figure 3 shown, the obtained polyvinyl alcohol-sulfuric acid gel has excellent cutability and can be cut into any shape according to the changes in the application scenario. In addition, it also has good flexibility and can still maintain excellent adhesiveness after undergoing large deformations.

[0028] Example 3:

[0029] A mixed solution was obtained by stirring concentrated sulfuric acid with a mass fraction of 98% and deionized water at a mass ratio of 1:1 for 8 minutes. Subsequently, polyvinyl alcohol powder of type 2488 with a total mass equal to that of concentrated sulfuric acid or deionized water was added in four portions to the mixed solution, and magnetically stirred at 90 °C for 3 hours at a constant speed until the mixture changed from a turbid state to clear and transparent to form a gel. Then it was placed in a drying oven at 80 °C and left standing for 4 hours to remove the bubbles in the gel.

[0030] As Figure 4 shown, the tensile strain of the obtained polyvinyl alcohol-sulfuric acid gel exceeds 1100%, demonstrating its excellent stretchability.

[0031] Example 4:

[0032] A mixed solution was obtained by stirring concentrated sulfuric acid with a mass fraction of 98% and deionized water at a mass ratio of 1:1 for 7 minutes. Subsequently, polyvinyl alcohol powder of type 1799 with a total mass equal to that of concentrated sulfuric acid or deionized water was added in three portions to the mixed solution, and magnetically stirred at 85 °C for 2.5 hours at a constant speed until the mixture changed from a turbid state to clear and transparent to form a gel. Then it was placed in a drying oven at 85 °C and left standing for 3.5 hours to remove the bubbles in the gel.

[0033] The variation law of the adhesive force of the obtained polyvinyl alcohol-sulfuric acid gel with temperature is as Figure 5As shown, it can bond a 200g weight at room temperature, providing an adhesive force exceeding 3.5 KPa, which is sufficient to ensure that it can still adhere well to the driving material after the driving cycle.

[0034] Example 5:

[0035] Mix concentrated sulfuric acid with a mass fraction of 98% and deionized water in a mass ratio of 1:1 and stir for 9 minutes to obtain a mixed solution. Subsequently, add 2488-type polyvinyl alcohol powder with a total mass equal to that of concentrated sulfuric acid or deionized water in 4 portions to the mixed solution, and use magnetic stirring to stir evenly at 95 °C for 3.5 hours until the mixture changes from a turbid state to clear and transparent and forms a gel. Place it in an 80 °C drying oven and let it stand for 3 hours to remove the bubbles in the gel.

[0036] At different storage temperatures, the variation law of the mass ratio of the obtained polyvinyl alcohol-sulfuric acid gel with the storage time is as Figure 6 shown. The reaction system of the all-solid-state electrochemical driver at room temperature will not change significantly within 30 days, thus ensuring its excellent cycle durability and stability.

[0037] Example 6:

[0038] Mix concentrated sulfuric acid with a mass fraction of 98% and deionized water in a mass ratio of 1:1 and stir for 5 minutes to obtain a mixed solution. Subsequently, add 1788-type polyvinyl alcohol powder with a total mass equal to that of concentrated sulfuric acid or deionized water in 2 portions to the mixed solution, and use magnetic stirring to stir evenly at 80 °C for 2 hours until the mixture changes from a turbid state to clear and transparent and forms a gel. Place it in a 75 °C drying oven and let it stand for 3 hours to remove the bubbles in the gel. Subsequently, grow black phosphorus on a copper foil by pulsed laser deposition method in a vacuum environment of 1×10 -8 Torr. The thickness ratio of black phosphorus to the copper foil is 1.5:1. Use a spin coater to spin-coat the gel standing by on the driving material at a speed of 5000 revolutions per minute within 2 minutes to form an intermediate polyvinyl alcohol-sulfuric acid gel layer with a thickness of 0.1 μm. Subsequently, attach a platinum mesh electrode to the intermediate polyvinyl alcohol-sulfuric acid gel solid electrolyte, and use the spin coater to spin-coat the gel standing by on the platinum mesh electrode at the same speed and the same time to form an upper polyvinyl alcohol-sulfuric acid gel solid electrolyte. Let the obtained all-solid-state electrochemical driver stand in a 20 °C environment for 20 hours.

[0039] The variation law of the driving displacement of this all-solid-state electrochemical driver with the driving voltage is as Figure 7 shown. The electrochemical driving effect becomes stronger with the increase of the driving voltage.

[0040] The above-described embodiments are only preferred specific embodiments of the present invention and do not constitute a limitation on the protection scope of the technical solution. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A all-solid-state electrochemical driver, characterized in that, It is composed of a metal foil, a driving material, an intermediate polyvinyl alcohol-sulfuric acid gel solid electrolyte, a platinum mesh electrode, and an upper polyvinyl alcohol-sulfuric acid gel solid electrolyte in sequence. Among them, the intermediate polyvinyl alcohol-sulfuric acid gel solid electrolyte and the upper polyvinyl alcohol-sulfuric acid gel solid electrolyte achieve bonding with adjacent layers through their own super strong adhesiveness; The preparation method of the all-solid-state electrochemical actuator is as follows: Mix concentrated sulfuric acid with a mass fraction of 98% and deionized water at a mass ratio of 1:1 and stir for 5 to 10 minutes to obtain a mixed solution. Subsequently, add 1788-type, 1799-type, 2488-type, or 2699-type polyvinyl alcohol powder with a total mass equal to that of concentrated sulfuric acid or deionized water in 2 to 5 portions to the mixed solution, and stir evenly at 80 to 100 °C for 2 to 4 hours using magnetic stirring until the mixture changes from a turbid state to clear and transparent and forms a gel. Place it in an oven at 75 to 85 °C and let it stand for 3 to 5 hours to remove the bubbles in the gel; subsequently, grow the driving material on the metal foil by pulsed laser deposition in a vacuum environment of 1×10 -8 ~9×10 -7 Torr. The thickness ratio of the driving material to the metal foil is (1 to 1.5):1; use a spin coater to spin coat the gel standing by on the driving material at a speed of 5000 to 10000 revolutions per minute within 2 to 4 minutes to form an intermediate polyvinyl alcohol-sulfuric acid gel solid electrolyte with a thickness of 0.1 to 0.5 μm. Subsequently, attach a platinum mesh electrode to the intermediate polyvinyl alcohol-sulfuric acid gel solid electrolyte, and use the spin coater to spin coat the gel standing by on the platinum mesh electrode at the same speed and for the same time again to form an upper polyvinyl alcohol-sulfuric acid gel solid electrolyte. Let the obtained all-solid-state electrochemical actuator stand in an environment at 20 to 25 °C for 20 to 24 hours.

2. The all-solid-state electrochemical actuator according to claim 1, wherein The metal foil is made of red gold foil, silver foil, copper foil, aluminum foil or tungsten foil with a thickness of 1-5μm.

3. The all-solid-state electrochemical actuator according to claim 1, characterized in that, The driving material is made of black phosphorus, apatite, metal-organic framework compound, transition metal dichalcogenide, carbon nanomaterial or metal carbon / nitride MXene with a thickness of 1-7.5μm.

4. The all-solid-state electrochemical actuator according to claim 3, characterized in that The transition metal dichalcogenide includes molybdenum disulfide, tungsten disulfide, molybdenum diselenide, molybdenum ditelluride and tungsten diselenide.

5. The all-solid-state electrochemical actuator according to claim 1, wherein, The metal foil and the driving material achieve tight bonding through the van der Waals force between layers formed during the pulsed laser deposition process.

6. The all-solid-state electrochemical actuator according to claim 1, characterized in that, The thickness of the intermediate polyvinyl alcohol-sulfuric acid gel solid electrolyte and the upper polyvinyl alcohol-sulfuric acid gel solid electrolyte is 0.1-0.5μm.

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