A flexible ionic actuator based on MXene / Ni-PBAs composite material and preparation method and application thereof

Abstract

The application discloses a flexible ionic actuator based on a MXene / Ni-PBAs composite material and a preparation method and application thereof, and the preparation method comprises the following steps: mixing nickel nitrate, sodium citrate, MXene and water, stirring uniformly, adding a potassium ferricyanide solution dropwise under stirring, sealing and aging, and separating and precipitating to obtain an electrode material; adding an ionic liquid and a Nafion film solution into an organic solvent, vacuum drying after heating and stirring, heat treating to obtain a polyelectrolyte layer, and punching a channel to obtain a pretreated polyelectrolyte layer; dissolving and dispersing the electrode material in the organic solvent to obtain an electrode material solution; coating a PEDOT:PSS-PH1000 solution on a substrate, adding the electrode material solution dropwise, and adhering into a film by using the PEDOT:PSS-PH1000 solution to obtain an electrode layer; and taking the electrode layer and the pretreated polyelectrolyte layer, and placing them in the order of the electrode layer, the pretreated polyelectrolyte layer and the electrode layer, and obtaining the flexible ionic actuator after heat pressing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of materials, in particular to a flexible ionic actuator based on MXene / Ni-PBAs composite material and a preparation method and application thereof. BACKGROUND

[0002] In recent years, as a kind of ionic electroactive polymer (iEAP) driver, the flexible ionic actuator has attracted great interest of researchers due to its excellent characteristics such as low cost, light weight, low voltage driving, large deformation, fast response, high strain and good air working stability, especially for the field of bionics, which has good application prospects in flexible robots, wearable touch feedback devices, stretchable and flexible electronic devices, micro-electro-mechanical systems, etc., and people hope to put it into use in the fields of medical treatment and military. However, at present, the flexible ionic actuator has obvious vacancy in the field of practical application, and can only complete some single device instructions and simple work, and has little practical value integrated in devices.

[0003] At present, with the growth of population and rapid economic development, the shortage of fresh water has become one of the most challenging and most serious global problems. Since seawater desalination is an ideal way to solve this problem, in recent years, researchers have been committed to finding a low-cost and efficient water purification technology. As a new type of water purification technology, high-capacity capacitive deionization (HCDI) has the advantages of low driving energy, low operating cost, reliable regeneration and environmental performance, and is likely to replace the traditional CDI technology to become a water purification technology to meet the growing demand for seawater desalination in the world in the future.

[0004] The Chinese patent application document with the publication number CN114649116A discloses a preparation method of MXene / MOFs electrode material, including the following steps: preparation of Ni(NO3)2·6H2O and MXene mixed solution; preparation of terephthalic acid solution; preparation of precursor solution; preparation of MXene / Ni MOF electrode material. It also discloses a MXene / MOFs ionic electrochemical driver, including the following steps: preparation of MXene / MOFs electrode film, preparation of composite intermediate layer, and formation of the electrochemical driver with a composite layer structure in a hot pressing mode of the MXene / MOFs electrode film, the composite intermediate layer and the MXene / MOFs electrode film. The electrochemical driver obtained by using the disclosed technical solution has larger driving performance, higher stress, lower driving voltage and wider driving response frequency, but the electrochemical driver cannot be used for seawater desalination. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a new flexible ionic actuator which can be used in a seawater desalination device and has excellent seawater desalination performance and good self-cleaning performance.

[0006] The present application solves the above technical problems by the following technical means:

[0007] A preparation method of a flexible ionic actuator based on a MXene / Ni-PBAs composite material, comprising the following steps:

[0008] S1, mixing nickel nitrate, sodium citrate and MXene with water and stirring uniformly, adding potassium ferricyanide solution dropwise under stirring, sealing and aging after dropwise addition is completed, and separating the precipitate product to obtain a MXene / Ni-PBAs composite electrode material;

[0009] S2, adding an ionic liquid and a Nafion film solution into an organic solvent, vacuum drying after heating and stirring, and then performing heat treatment to obtain a Nafion polyelectrolyte layer;

[0010] S3, punching a channel in the Nafion polyelectrolyte layer to obtain a pretreated polyelectrolyte layer; dissolving and dispersing the MXene / Ni-PBAs composite electrode material in the S1 in an organic solvent to obtain an electrode material solution; coating a PEDOT:PSS-PH1000 solution on a substrate, and adding the electrode material solution to adhere into a film by using the PEDOT:PSS-PH1000 solution to obtain an electrode layer;

[0011] S4, taking the electrode layer and the pretreated polyelectrolyte layer, and placing them in the order of electrode layer, pretreated polyelectrolyte layer, and electrode layer, and then performing hot pressing to obtain the flexible ionic actuator based on the MXene / Ni-PBAs composite material.

[0012] Preferably, in S1, the mass ratio of the MXene to the nickel nitrate is 0.6-1.5:0.29; and the molar ratio of the nickel nitrate, the sodium citrate, and the potassium ferricyanide is 1:0.6-1.5:0.5.

[0013] Preferably, in S1, the sealing and aging time is 24h.

[0014] Preferably, in S2, the ionic liquid is EMImBF4; and the organic solvent is N,N-dimethylacetamide; specifically, the ionic liquid is EMImBF4, which is stable and has a large difference in the radius of anions and cations, and is beneficial to deformation.

[0015] Preferably, in S2, the mass fraction of the Nafion film solution is 5%, and the mass ratio of the ionic liquid, the Nafion film solution, and the organic solvent is 1:10-30:20-30.

[0016] Beneficial effect: the thickness of the polyelectrolyte layer can be effectively controlled.

[0017] Preferably, in S2, the heating stirring comprises heating to 50 DEG C and stirring for 5h; the vacuum drying temperature is 90 DEG C, the time is 12h, the heat treatment temperature is 120 DEG C, and the time is 2h.

[0018] Preferably, in S3, the mass ratio of PEDOT:PSS-PH1000 to MXene / Ni-PBAs composite electrode material used is 1-2:1-2.

[0019] Beneficial effect: controlling the reasonable mass ratio of PEDOT:PSS to electrode material can make the electrode layer have good conductivity.

[0020] Preferably, in S1, the MXene is MXene nanosheet.

[0021] Preferably, in S1, the potassium ferricyanide solution is potassium ferricyanide aqueous solution.

[0022] Preferably, in S1, the dropping speed of the potassium ferricyanide solution is 1 drop per second.

[0023] Beneficial effect: by controlling the titration speed and aging time, the final morphology of Ni-PBAs can be effectively controlled as cubic structure.

[0024] The application further provides a flexible ionic actuator based on MXene / Ni-PBAs composite material, which is prepared by the preparation method of the flexible ionic actuator based on MXene / Ni-PBAs composite material.

[0025] Beneficial effect: the flexible ionic actuator based on MXene / Ni-PBAs composite material prepared by the application has the dual abilities of deformation and seawater desalination adsorption.

[0026] The application further provides an application of the flexible ionic actuator based on MXene / Ni-PBAs composite material in seawater desalination.

[0027] The application further provides a self-cleaning seawater desalination device containing the flexible ionic actuator based on MXene / Ni-PBAs composite material.

[0028] The application has the following advantages:

[0029] The application has the following advantages: +The selective adsorption of the ions in the seawater is realized, so as to achieve the purpose of seawater desalination, and the desalinated water is collected, and the problem of the stacking of the sheets of the MXene used as the electrode material is improved, so as to cause the problem of insufficient ion storage space. After the actuator film desorbs, various impurities will inevitably accumulate on the surface of the actuator film, at this time, the deformation process is continuously generated by applying the bidirectional voltage again, so as to release the impurities of the actuator film, and the cleaning and reuse of the seawater desalination device are realized. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a preparation flowchart of the electrode layer material in the embodiment 1 of the present application.

[0031] Figure 2 It is a preparation flowchart of the pretreated Nafion polyelectrolyte layer in the embodiment 1 of the present application.

[0032] Figure 3 It is an SEM diagram of the surface of the electrode layer material prepared in the embodiment 1 of the present application.

[0033] Figure 4 It is an assembly diagram of the three-layer structure of the ion actuator in the embodiment 1 of the present application.

[0034] Figure 5 It is a whole schematic diagram of the self-cleaning seawater desalination device in the present application.

[0035] Figure 6 It is a decomposition structure (component) schematic diagram of the self-cleaning seawater desalination device in the present application.

[0036] Figure 7 It is a seawater desalination (deionization) principle diagram of the flexible ion actuator prepared in the embodiment 1 of the present application.

[0037] Figure 8 It is a deformation data diagram of the flexible ion actuator prepared in the embodiment 1 of the present application (0.1-3V voltage, 0.1Hz response deformation peak interval displacement data). DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0039] In the following examples, the test materials and reagents used, etc., can be obtained from commercial channels unless otherwise specified.

[0040] Unless otherwise specified in the examples, all techniques and conditions described in the examples are those that are conventionally used in the art or those described in the literature or in the product manual.

[0041] Example 1

[0042] A flexible ionic actuator based on MXene / Ni-PBAs composite material, comprising an electrode layer and an electrolyte layer, the electrolyte layer is located between the two electrode layers, referring to Figure 1 and Figure 2 The preparation method specifically comprises the following steps:

[0043] (1) Preparation of electrode layer material: in-situ growth of Ni-PBAs on MXene nanosheets by coprecipitation method:

[0044] ① 1 mmol of Ni(NO3)2·6H2O, 1.5 mmol of C6H5Na3O7 (sodium citrate) and 1.5 g of MXene nanosheets were dispersed in 200 ml of deionized water for magnetic stirring (25℃, 350 rpm) mixing to obtain a mixed solution;

[0045] ② 0.5 mmol of K3Fe(CN)6 (potassium ferricyanide) was uniformly dispersed in 50 ml of deionized water, slowly added dropwise to the mixed solution obtained in the above ①, and continuously stirred with a magnet (25℃, 350 rpm). After titration, it was sealed and aged for 24 h, then centrifuged, washed and dried to obtain the precipitate product, i.e. the electrode layer material. The in-situ growth of the obtained electrode layer material product is shown in Figure 3 SEM diagram, from which it can be seen that Figure 3 Ni-PBAs in the form of square sugar are grown on the MXene sheet layer.

[0046] (2) Preparation of Nafion polyelectrolyte layer

[0047] 0.272 g of ionic liquid (EMImBF4) and 5% wt of 8.16 g of Nafion membrane solution were added to 5.44 g of organic solvent N-N-dimethylacetamide (DMAC), heated and stirred (50℃, 700 rpm) for 5 h, then poured into a casting mold, vacuum dried at 90℃ for 12 h, then heated to 120℃ for 2 h; The prepared Nafion polyelectrolyte layer was pretreated by punching a channel, i.e. the pretreated Nafion polyelectrolyte layer was prepared.

[0048] (3) Assembly of MXene / Ni-PBAs composite material ionic actuator

[0049] The electrode layer material obtained in (1) is dissolved and dispersed in an organic solvent N-N-dimethylformamide (DMF), and an electrode layer is obtained by using a PEDOT:PSS-PH1000 solution dropped on a glass substrate to adhere and form a film, and the mass ratio of the used PEDOT:PSS-PH1000 to the electrode layer material is 1:2; then two pieces of electrode layers are taken and placed on the top and bottom of the pretreated Nafion polyelectrolyte layer respectively, and then hot-pressed to obtain a three-layer structure flexible ionic actuator based on MXene / Ni-PBAs composite material, and the preparation schematic is as shown in Figure 4 .

[0050] Example 2

[0051] The difference between this embodiment and Example 1 is that the mass of MXene nanosheet is adjusted to 0.6g.

[0052] Example 3

[0053] The difference between this embodiment and Example 1 is that the Nafion polyelectrolyte layer is replaced by Nafion 117 (DuPont); the film is too thick, and the seawater desalination effect is poor.

[0054] Example 4

[0055] The difference between this embodiment and Example 1 is that the mass ratio of ionic liquid, Nafion film solution, and organic solvent (DMAC) is adjusted to 1:10:30.

[0056] Example 5

[0057] The difference between this embodiment and Example 1 is that the mass ratio of ionic liquid, Nafion film solution, and organic solvent (DMAC) is adjusted to 1:12.5:30.

[0058] Example 6

[0059] The difference between this embodiment and Example 1 is that the mass ratio of PEDOT:PSS-PH1000 to the electrode layer material is adjusted to 1:1.

[0060] Example 7

[0061] The difference between this embodiment and Example 1 is that the mass ratio of PEDOT:PSS-PH1000 to the electrode layer material is adjusted to 2:1.

[0062] Example 8

[0063] A self-cleaning seawater desalination device based on a flexible ionic actuator of MXene / Ni-PBAs composite material, and the schematic diagram is as shown in Figure 5 , Figure 6 .

[0064] The self-cleaning seawater desalination device comprises a water inlet 9, a water inlet bin 1, a microfiltration membrane 2, a first flow bin 3 and a second flow bin 7, an ionic actuator 5, a bidirectional power component 4, a storage bin 8, and a sewage / waste water bin 6; the water inlet 9 is located on the water inlet bin 1, and the water inlet bin 1, the microfiltration membrane 2, the first flow bin 3, the ionic actuator 5, the second flow bin 7, and the storage bin 8 are connected in sequence, and the bidirectional power component 4 and the sewage / waste water bin 6 are attached to both sides of the overall assembly.

[0065] Working principle: when the self-cleaning seawater desalination device is applied with voltage, due to the cation selective permeability of the Nafion polyelectrolyte layer, Na + in seawater will pass through the Nafion membrane layer and move towards the cathode, when Na + migrates to the surface of the electrode layer, the in-situ grown Ni-PBAs on the MXene nanosheet will undergo a redox reaction with Na + , realizing the adsorption of high-concentration seawater (containing Na + ), thereby completing seawater desalination, and when the voltage is turned off, low-concentration fresh water will be released and flow into the storage bin through the flow bin. However, when the flexible ionic actuator is applied with a bidirectional voltage of a certain frequency, EMIm + in the Nafion polyelectrolyte layer will migrate towards the cathode, and BF4 - will migrate towards the anode, resulting in the separation of cations and anions on the electrode side, and the ionic radius of EMIm + in the ionic liquid is much larger than that of BF4 - , which will eventually cause the actuator to bend towards the anode side, and through the shaking process caused by the continuous deformation, the impurities remaining on the ionic actuator will be released into the sewage / waste water bin, realizing the self-cleaning process of seawater desalination for subsequent recycling.

[0066] Seawater desalination test method: the desalination performance of MXene / Ni-PBAs in a saltwater environment was studied by using 500mg / L concentration of sodium chloride and 1.4V voltage. The ion removal step was carried out by applying voltage for a certain time, and the captured ions were released by applying negative voltage (-1.4V) for a certain time. The 500mg / L concentration of sodium chloride aqueous solution (2.5L) was pumped into the CDI device using a peristaltic pump, and then flowed into another tank. (Conventional deionization test method). The reason why the thin film device prepared from the material has desalination ability is related to the ion migration mechanism of the ionic actuator (as shown in Figure 7 ), thereby achieving the purpose of seawater desalination.

[0067] Figure 8The deformation data graph (0.1-3V voltage, 0.1Hz response deformation peak displacement data) of the flexible ionic actuator prepared in Example 1 of the present application; from Figure 8 It can be seen that the device prepared from the material can realize effective deformation under 0.1-3V voltage, thereby meeting the function of completing self-cleaning by deformation of the ionic actuator for the designed seawater desalination device.

[0068] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for fabricating a flexible ion actuator based on MXene / Ni-PBAs composite material, characterized in that: Includes the following steps: S1. Nickel nitrate, sodium citrate and MXene are mixed with water and stirred until homogeneous. Potassium ferricyanide solution is added dropwise under stirring. After the addition is complete, the mixture is sealed and aged. The precipitate is separated to obtain MXene / Ni-PBAs composite electrode material. S2. Add the ionic liquid and Nafion membrane solution to an organic solvent, heat and stir, then place in a mold for vacuum drying, and then perform heat treatment to obtain the Nafion polyelectrolyte layer. S3. Drill holes in the Nafion polyelectrolyte layer to obtain a pretreated polyelectrolyte layer; dissolve and disperse the MXene / Ni-PBAs composite electrode material in S1 in an organic solvent to obtain an electrode material solution; coat the substrate with PEDOT:PSS-PH1000 solution, drop the electrode material solution and use PEDOT:PSS-PH1000 solution to bond and form a film to obtain an electrode layer. S4. Take the electrode layer and the pretreated polyelectrolyte layer, place them in the order of electrode layer, pretreated polyelectrolyte layer, and electrode layer, and hot press them to obtain the flexible ion actuator based on MXene / Ni-PBAs composite material.

2. The method for preparing a flexible ion actuator based on MXene / Ni-PBAs composite material according to claim 1, characterized in that: In S1, the mass ratio of MXene to nickel nitrate is 0.6-1.5:0.29; the molar ratio of nickel nitrate, sodium citrate, and potassium ferricyanide is 1:0.6-1.5:0.

5.

3. The method for fabricating a flexible ion actuator based on MXene / Ni-PBAs composite material according to claim 1, characterized in that: In S1, the sealing and aging time is 24 hours.

4. The method for preparing a flexible ion actuator based on MXene / Ni-PBAs composite material according to claim 1, characterized in that: In S2, the ionic liquid is EMImBF4; the organic solvent is N,N-dimethylacetamide.

5. The method for fabricating a flexible ion actuator based on MXene / Ni-PBAs composite material according to claim 1, characterized in that: In S2, the mass fraction of the Nafion membrane solution is 5%, and the mass ratio of the ionic liquid, the Nafion membrane solution, and the organic solvent is 1:10-30:20-30.

6. The method for preparing a flexible ion actuator based on MXene / Ni-PBAs composite material according to claim 1, characterized in that: In S2, the heating and stirring includes heating to 50°C and stirring for 5 hours; the vacuum drying temperature is 90°C and the time is 12 hours; and the heat treatment temperature is 120°C and the time is 2 hours.

7. The method for preparing a flexible ion actuator based on MXene / Ni-PBAs composite material according to any one of claims 1-6, characterized in that: In S3, the mass ratio of PEDOT:PSS-PH1000 to MXene / Ni-PBAs composite electrode material is 1-2:1-2.

8. A flexible ion actuator based on MXene / Ni-PBAs composite material, characterized in that: It is prepared by the method of any one of claims 1-7 for the preparation of a flexible ion actuator based on MXene / Ni-PBAs composite material.

9. The application of a flexible ion actuator based on MXene / Ni-PBAs composite material as described in claim 8 in seawater desalination.

10. A self-cleaning seawater desalination device, characterized in that: The flexible ion actuator based on MXene / Ni-PBAs composite material as described in claim 8 contains the flexible ion actuator described in claim 8.

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