Inorganic double perovskite / PVDF-based composite piezoelectric film and preparation method and application thereof

Abstract

The invention belongs to the technical field of new piezoelectric materials, and particularly relates to an inorganic double perovskite / PVDF (polyvinylidene fluoride)-based composite piezoelectric film as well as a preparation method and application thereof. The composite piezoelectric film is a composite piezoelectric film formed by in-situ growth of Zr-doped Cs2Ag0. 3Na0. 7InCl6 double perovskite in a PVDF (Polyvinylidene Fluoride) matrix. The invention improves the traditional synthesis method of a piezoelectric composite material by a two-step method, discloses a preparation method for growing inorganic double perovskite, and cooperates with the content regulation and control of Zr-doped Cs2Ag0. 3Na0. 7InCl6 double perovskite, thereby enhancing the piezoelectric property of the PVDF-based composite piezoelectric film. According to the preparation method disclosed by the invention, uniform dispersion of the double perovskite as a filler in a PVDF matrix can be effectively realized, growth of a piezoelectric phase beta phase in PVDF is improved, migration and aggregation of electrons are promoted, establishment of a strong built-in electric field is facilitated to amplify spontaneous polarization of a dipole, spontaneous polarization performance is optimized, and finally improvement of piezoelectric performance is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of new piezoelectric materials, and particularly relates to an inorganic double perovskite / PVDF-based composite piezoelectric film, a preparation method thereof, and an application thereof. Background Art

[0002] As an innovative energy conversion technology, piezoelectric nanogenerators can convert mechanical motion into electrical energy, which is not only environmentally friendly but also has broad application prospects. Their applications in the fields of energy harvesting, self-powered sensor networks, and wearable electronic devices are particularly prominent, providing new possibilities for achieving sustainable development and intelligent technology.

[0003] Polyvinylidene fluoride (PVDF) is a semi-crystalline polymer material with excellent properties. It is well-known for its outstanding chemical corrosion resistance, oxidation resistance, and ultraviolet resistance. These properties make PVDF an ideal choice for constructing flexible and durable wearable energy conversion devices. Notably, PVDF has five different crystalline phases, and the β-phase is particularly favored due to its excellent ferroelectric, piezoelectric, and pyroelectric properties. To enhance the piezoelectric effect of PVDF, researchers have found that introducing perovskite nanocrystal fillers into its matrix is an effective method, which can significantly increase the proportion of the β-phase in PVDF, thereby enhancing the overall piezoelectric response.

[0004] The traditional preparation of PVDF films containing perovskite fillers involves two main steps: first, synthesizing perovskite nanocrystals, and then mixing them with PVDF and forming a composite film through techniques such as casting or blade coating. However, this method faces a key problem: using solvents such as dimethylformamide may degrade the surface of the pre-synthesized perovskite crystals, resulting in non-uniform distribution and aggregation of perovskite in the PVDF matrix, which will weaken the performance of the final product. To address this challenge, researchers have proposed an in-situ growth strategy, that is, directly adding perovskite precursor substances to the PVDF solution, allowing perovskite crystals to crystallize naturally during the film forming process. This method not only ensures a stable interface between perovskite crystals and the PVDF matrix but also achieves consistency in perovskite crystal size and uniform spatial distribution, greatly optimizing the performance of the composite material.

[0005] Although some studies have explored the possibility of using lead halide perovskites to fill PVDF films through in-situ growth methods, the research on filling with cation-doped all-inorganic lead-free double perovskites remains an underdeveloped area. In addition, more in-depth research is still needed on the internal factors for further improving the piezoelectric properties of such composites through in-situ growth. With the deepening of the understanding of these new materials and methods, we can expect to witness the development of more efficient, environmentally friendly, and high-performance piezoelectric nanogenerators, which will drive the maturity of a series of products and services relying on this technology. Summary of the Invention

[0006] In view of the above deficiencies in the prior art, the present invention provides an inorganic double perovskite / PVDF-based composite piezoelectric film, its preparation method, and applications.

[0007] One object of the present invention is achieved through the following technical solutions:

[0008] An inorganic double perovskite / PVDF-based composite piezoelectric film, wherein the inorganic double perovskite in the composite piezoelectric film is Zr-doped Cs 2 Ag 0.3 Na 0.7 InCl 6 double perovskite, and the composite piezoelectric film is a composite piezoelectric film in which Zr-doped Cs 2 Ag 0.3 Na 0.7 InCl 6 double perovskite grows in-situ in the PVDF matrix.

[0009] Preferably, the mass percentage of Zr-doped Cs 2 Ag 0.3 Na 0.7 InCl 6 double perovskite in the PVDF matrix is 3-12 wt%.

[0010] Preferably, the β-phase content of the inorganic double perovskite / PVDF-based composite piezoelectric film is 80-90 wt%. PVDF exists in five different crystalline phases, including α, β, γ, δ, and ε phases, each with different crystal structures and physical properties, and β has excellent ferroelectric, piezoelectric, and pyroelectric properties.

[0011] Preferably, the piezoelectric coefficient of the inorganic double perovskite / PVDF-based composite piezoelectric film is 14-16 pC / N.

[0012] Preferably, the dielectric constant ε value of the inorganic double perovskite / PVDF-based composite piezoelectric film at 30-60 kHz is 30-45.

[0013] More preferably, the inorganic double perovskite / PVDF-based composite piezoelectric film has a dielectric constant ε value of 32.15 at 50 kHz.

[0014] Another object of the present invention is achieved by the following technical solutions:

[0015] A preparation method of an inorganic double perovskite / PVDF-based composite piezoelectric film, the preparation method comprising the following steps: adding zirconium chloride (ZrCl 4 ), cesium chloride (CsCl), silver chloride (AgCl), sodium chloride (NaCl), indium chloride (InCl 3 ) and polyvinylidene fluoride (PVDF) into an organic reagent, stirring and dissolving to obtain a precursor solution; coating the precursor solution onto a substrate, and drying to obtain a Zr-doped Cs 2 Ag 0.3 Na 0.7 InCl 6 double perovskite / PVDF-based composite piezoelectric film.

[0016] Preferably, the mass ratio of zirconium chloride, cesium chloride, silver chloride, sodium chloride and indium chloride is (20-100):(30-140):(1-20):(1-20):(20-100). More preferably, it is (50-90):(70-110):(10-15):(10-15):(50-90).

[0017] Preferably, the mass ratio of the total mass of zirconium chloride, cesium chloride, silver chloride, sodium chloride and indium chloride to the mass of polyvinylidene fluoride is (0.01-0.15):1. More preferably, it is (0.07-0.10):1.

[0018] Preferably, the polyvinylidene fluoride (PVDF) is added in the form of powder, and the particle size of the polyvinylidene fluoride powder is 1-100 μm.

[0019] Preferably, the organic reagent includes one or more of dimethyl sulfoxide (DMSO), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethylformamide (DMF), acetone, tetrahydrofuran (THF), cyclohexanone. More preferably, it is dimethyl sulfoxide (DMSO).

[0020] Preferably, the ratio of the total mass of zirconium chloride, cesium chloride, silver chloride, sodium chloride, indium chloride and polyvinylidene fluoride to the organic reagent is 1 g:(8-12) mL.

[0021] Preferably, the stirring and dissolving includes the following steps: stirring at a rotation speed of 100 - 600 r / min at 60 - 100 °C for 1 - 10 h, and stirring until completely dissolved to obtain a mixed precursor solution.

[0022] Preferably, the precursor solution is uniformly coated onto a glass substrate using a doctor blade, and then the glass substrate coated with the precursor solution is transferred into an oven for drying.

[0023] Preferably, the coating thickness of the precursor solution is 200 - 1000 μm, and the coating area is 1 - 100 cm 2 .

[0024] Preferably, the drying temperature is 60 - 180 °C, and the drying time is 1 - 10 h.

[0025] The third object of the present invention is achieved by the following technical solutions:

[0026] A piezoelectric nanogenerator, whose components include the above-mentioned inorganic double perovskite / PVDF-based composite piezoelectric film.

[0027] Preferably, the open-circuit voltage of the piezoelectric nanogenerator is 40 - 50 V, and the short-circuit current density is 8 - 12 μA·cm -2 .

[0028] Preferably, the piezoelectric nanogenerator can still maintain a stable electrical output after being subjected to a continuous impact force of 10 - 20 N and undergoing 10,000 - 20,000 cycles.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. An inorganic double perovskite / PVDF-based composite piezoelectric film and its preparation method provided by the present invention use all-inorganic lead-free double perovskite for filling, and through in-situ growth technology, Zr-doped Cs 2 Ag 0.3 Na 0.7 InCl 6 double perovskite is in-situ grown in the PVDF matrix. Compared with the composite piezoelectric film prepared by the traditional two-step method, the in-situ grown Zr-doped double perovskite has a more uniform and better dispersion in the composite film, which helps to improve the growth of the piezoelectric phase β-phase in PVDF, promotes the migration and aggregation of electrons, is beneficial to establishing a strong built-in electric field to amplify the spontaneous polarization rate of dipoles, optimizes the spontaneous polarization performance, and realizes the improvement of piezoelectric performance. And it has better crystallization performance and higher dielectric constant, and these factors further make the in-situ grown composite piezoelectric film have more excellent piezoelectric performance.

[0031] 2. The present invention synthesizes Zr-doped Cs2 Ag 0.3 Na 0.7 InCl 6 The process of the double perovskite / PVDF-based composite piezoelectric film is simple and controllable, with good repeatability in large-area preparation. Compared with the two-step method, it reduces the production process and cost, lowers energy consumption, and realizes green and sustainable development.

[0032] 3. The Zr-doped Cs of the present invention 2 Ag 0.3 Na 0.7 InCl 6 The double perovskite / PVDF-based composite piezoelectric film can be applied in piezoelectric nanogenerators. Compared with the PVDF-based piezoelectric material system, it has a higher open-circuit voltage and short-circuit current density. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 For the Zr-doped Cs prepared in Example 1 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 Scanning electron microscope (SEM) image of the double perovskite / PVDF-based composite piezoelectric film.

[0034] Figure 2 For the Zr-doped Cs prepared in Example 1 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 X-ray diffraction (XRD) pattern of the double perovskite / PVDF-based composite piezoelectric film.

[0035] Figure 3 For the Zr-doped Cs prepared in Example 1 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 Dielectric constant graph of the double perovskite / PVDF-based composite piezoelectric film at 1 - 1000 kHz.

[0036] Figure 4 For the Zr-doped Cs prepared by using Example 1 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 Open-circuit voltage and short-circuit current graph of the piezoelectric nanogenerator constructed with the double perovskite / PVDF-based composite piezoelectric film.

[0037] Figure 5 For the Zr-doped Cs prepared in Example 2 of the present invention 2 Ag 0.3 Na 0.7InCl 6 Scanning electron microscopy (SEM) image of the double perovskite / PVDF-based composite piezoelectric film.

[0038] Figure 6 Cs doped with Zr prepared in Example 3 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 Scanning electron microscopy (SEM) image of the double perovskite / PVDF-based composite piezoelectric film.

[0039] Figure 7 Cs doped with Zr prepared in Example 4 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 Scanning electron microscopy (SEM) image of the double perovskite / PVDF-based composite piezoelectric film.

[0040] Figure 8 Scanning electron microscopy (SEM) image of the PVDF-based piezoelectric film prepared in Comparative Example 1 of the present invention.

[0041] Figure 9 Cs doped with Zr prepared in Examples 1-4 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 X-ray diffraction (XRD) comparison chart of the double perovskite / PVDF-based composite piezoelectric film and the PVDF-based piezoelectric film prepared in Comparative Example 1.

[0042] Figure 10 Cs doped with Zr prepared in Examples 1-4 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 Fourier transform infrared spectroscopy (FTIR) comparison chart of the double perovskite / PVDF-based composite piezoelectric film and the PVDF-based piezoelectric film prepared in Comparative Example 1.

[0043] Figure 11 Cs doped with Zr prepared in Examples 1-4 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 Dielectric constant comparison chart of the double perovskite / PVDF-based composite piezoelectric film and the PVDF-based piezoelectric film prepared in Comparative Example 1 at 1-1000 kHz.

[0044] Figure 12 Cs doped with Zr prepared by using Examples 1-4 of the present invention 2 Ag0.3 Na 0.7 InCl 6 Open-circuit voltage comparison diagram of the piezoelectric nanogenerator constructed by the double perovskite / PVDF-based composite piezoelectric film and the PVDF-based piezoelectric film prepared in Comparative Example 1.

[0045] Figure 13 Zr-doped Cs prepared in Comparative Example 2 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 Scanning electron microscope (SEM) image of the double perovskite / PVDF-based composite piezoelectric film.

[0046] Figure 14 Zr-doped Cs prepared by using Example 1 and Comparative Example 2 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 Open-circuit voltage and short-circuit current diagram of the piezoelectric nanogenerator constructed by the double perovskite / PVDF-based composite piezoelectric film.

[0047] Figure 15 Zr-doped Cs prepared by using Example 1 and Comparative Example 2 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 Stability comparison diagram of the piezoelectric nanogenerator constructed by the double perovskite / PVDF-based composite piezoelectric film. Detailed implementation manners

[0048] The following combines specific examples and drawings to further describe and explain the technical solutions of the present invention. It should be understood that the specific examples described herein are only used to illustrate the present invention and not to limit the scope of the present invention. Moreover, the drawings used herein are only for better explaining the disclosed content of the present invention and do not have a limiting effect on the protection scope. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0049] Example 1

[0050] The preparation method of the inorganic double perovskite / PVDF-based composite piezoelectric film in this example includes the following steps:

[0051] (1) 72.00 mg of ZrCl 4 , 104.04 mg of CsCl, 13.32 mg of AgCl, 12.63 mg of NaCl, 68.34 mg of InCl 3Put the 3g PVDF powder into a 50 mL round-bottom flask, add 30 mL of DMSO, and stir at 100 °C at a speed of 200 r / min for 5 h until the precursor is evenly mixed to obtain a viscous and homogeneous precursor solution;

[0052] (2) Take 4 mL of the above precursor solution, and use a doctor blade to evenly coat the precursor solution on a glass substrate with a coating thickness of 1000 μm; then put it into an oven, dry it at 100 °C for 3 h and take it out to obtain a Zr-doped Cs with a mass ratio of 9 wt% 2 Ag 0.3 Na 0.7 InCl 6 double perovskite / PVDF-based composite piezoelectric film.

[0053] Figure 1 For the Zr-doped Cs prepared in Example 1 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 Scanning electron microscope (SEM) image of the double perovskite / PVDF-based composite piezoelectric film, indicating that Zr-doped Cs uniformly distributed in the PVDF polymer film was successfully prepared 2 Ag 0.3 Na 0.7 InCl 6 crystals with a size of about 100 nm.

[0054] Figure 2 For the Zr-doped Cs prepared in Example 1 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 X-ray diffraction (XRD) pattern of the double perovskite / PVDF-based composite piezoelectric film, indicating that Zr-doped Cs was successfully grown in the composite film 2 Ag 0.3 Na 0.7 InCl 6 double perovskite, and at the same time, after adding Zr-doped Cs 2 Ag 0.3 Na 0.7 InCl 6 to PVDF, the peak of the α-phase in PVDF gradually disappeared, while the peak of the β-phase (110) became obvious. This indicates that the addition of Zr-doped Cs 2 Ag 0.3 Na 0.7 InCl 6 promotes the phase transition of PVDF from the α-phase to the β-phase (piezoelectric phase).

[0055] Figure 3For the Zr-doped Cs prepared in Example 1 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 Dielectric constant graph of the double perovskite / PVDF-based composite piezoelectric film at 1 - 1000 kHz, where the dielectric constant value at 50 kHz reaches 32.15, which means that the Zr-doped Cs 2 Ag 0.3 Na 0.7 InCl 6 grown in-situ in the PVDF matrix generates a strong polarization electric field, promoting the phase transition.

[0056] Figure 4 For the Zr-doped Cs prepared in Example 1 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 Open-circuit voltage and short-circuit current graph of the piezoelectric nanogenerator constructed with the double perovskite / PVDF-based composite piezoelectric film, where under the action of 3 Hz and 20 N force, the open-circuit voltage (V oc ) and short-circuit current density (I sc ) of the constructed piezoelectric nanogenerator are 44.4 V and 10 μA·cm -2 .

[0057] Example 2

[0058] The difference between this example and Example 1 is only that in step (1), the contents of ZrCl 4 , CsCl, AgCl, NaCl and InCl 3 are 24.00 mg, 34.68 mg, 4.44 mg, 4.21 mg and 22.78 mg respectively, and the rest is the same as in Example 1.

[0059] Figure 5 For the Zr-doped Cs prepared in Example 2 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 Scanning electron microscope (SEM) graph of the double perovskite / PVDF-based composite piezoelectric film, indicating that the synthesized composite film contains a small amount of crystals with a tetrahedral structure.

[0060] Example 3

[0061] The difference between this example and Example 1 is only that in step (1), the contents of ZrCl 4 , CsCl, AgCl, NaCl and InCl 3The contents are 48.00 mg, 69.36 mg, 8.88 mg, 8.42 mg and 45.56 mg respectively, and the rest is the same as in Example 1.

[0062] Figure 6 This is the Zr-doped Cs prepared in Example 3 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 Scanning electron microscope (SEM) image of the double perovskite / PVDF-based composite piezoelectric film, indicating that the crystals with tetrahedral structure in the synthesized composite film are significantly increased, and the crystal sizes are uniform, about 1-2 μm.

[0063] Example 4

[0064] The difference between this example and Example 1 is only that in step (1), ZrCl 4 , CsCl, AgCl, NaCl and InCl 3 The contents are 96.00 mg, 138.72 mg, 17.76 mg, 16.84 mg and 91.2 mg respectively, and the rest is the same as in Example 1.

[0065] Figure 7 This is the Zr-doped Cs prepared in Example 4 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 Scanning electron microscope (SEM) image of the double perovskite / PVDF-based composite piezoelectric film, indicating that obvious agglomeration phenomenon appears in the crystals in the synthesized composite film.

[0066] Comparative Example 1

[0067] The difference between this comparative example and Example 1 is only that in step (1), ZrCl is not added 4 , CsCl, AgCl, NaCl and InCl 3 , and the rest is the same as in Example 1.

[0068] Figure 8 This is the scanning electron microscope (SEM) image of the PVDF-based piezoelectric film prepared in Comparative Example 1 of the present invention, indicating that there are no perovskite crystals in the synthesized film.

[0069] Figure 9 This is the Zr-doped Cs prepared in Examples 1-4 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 X-ray diffraction (XRD) comparison chart of the double perovskite / PVDF-based composite piezoelectric film and the PVDF-based piezoelectric film prepared in Comparative Example 1, indicating that the in-situ grown Zr-doped Cs2 Ag 0.3 Na 0.7 InCl 6 Double perovskite has been successfully grown in PVDF, and in-situ grown Zr-doped Cs 2 Ag 0.3 Na 0.7 InCl 6 The double perovskite not only increases the crystallinity of the composite piezoelectric film but also successfully induces the complete transformation of the α-phase to the β-phase of PVDF.

[0070] Figure 10 For the Zr-doped Cs prepared in Examples 1 to 4 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 The Fourier transform infrared spectroscopy (FTIR) comparison diagram of the double perovskite / PVDF-based composite piezoelectric film and the PVDF-based piezoelectric film prepared in Comparative Example 1 further confirms the in-situ grown Zr-doped Cs 2 Ag 0.3 Na 0.7 InCl 6 The double perovskite successfully promotes the transformation of the α-phase to the β-phase of PVDF, and when Zr-doped Cs 2 Ag 0.3 Na 0.7 InCl 6 The mass ratio of the double perovskite is that of Example 1, and the promoting effect is the most obvious.

[0071] Figure 11 For the Zr-doped Cs prepared in Examples 1 to 4 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 The comparison diagram of the dielectric constants of the double perovskite / PVDF-based composite piezoelectric film and the PVDF-based piezoelectric film prepared in Comparative Example 1 at 1 to 1000 kHz shows that when Zr-doped Cs 2 Ag 0.3 Na 0.7 InCl 6 The mass ratio of the double perovskite is that of Example 1, and its dielectric constant also reaches the maximum value.

[0072] Figure 12 For the Zr-doped Cs prepared in Examples 1 to 4 of the present invention 2 Ag 0.3 Na 0.7 InCl 6Open-circuit voltage comparison diagram of the piezoelectric nanogenerator constructed by the double perovskite / PVDF-based composite piezoelectric film and the PVDF-based piezoelectric film prepared in Comparative Example 1, with its open-circuit voltage V oc With the in-situ growth of Zr-doped Cs 2 Ag 0.3 Na 0.7 InCl 6 As the weight ratio of the double perovskite increases, the piezoelectric signal increases significantly, reaching a maximum value of 43.2 V at the weight ratio of Example 1.

[0073] Comparative Example 2

[0074] The difference between this comparative example and Example 1 is only that the two-step method is used to prepare the PVDF-based composite piezoelectric film in this comparative example, which is as follows:

[0075] (1) Mix 72.00 mg of ZrCl 4 , 104.04 mg of CsCl, 13.32 mg of AgCl, 12.63 mg of NaCl, 68.34 mg of InCl 3 and 10 mL of HCl evenly in a 50 mL polytetrafluoroethylene inner liner, then transfer it to a stainless steel autoclave, dry it in an oven at 180 °C for 12 h, wash it with deionized water, perform centrifugation, and dry it in air at 60 °C for 3 h to obtain Zr-doped Cs 2 Ag 0.3 Na 0.7 InCl 6 double perovskite powder;

[0076] (2) Add 1 g of PVDF and 10 mL of N,N-dimethylformamide to a beaker, stir at 60 °C for 2 h to obtain a viscous and homogeneous mixed solution;

[0077] (3) Take 90 mg of the Zr-doped Cs 2 Ag 0.3 Na 0.7 InCl 6 double perovskite powder prepared in step (1) and add it to the mixed solution prepared in step (2), stir at 50 °C for 2 h to mix evenly to obtain a precursor solution;

[0078] (4) Take 4 mL of the precursor solution prepared in step (3), use a doctor blade to evenly coat the precursor solution on a glass substrate with a coating thickness of 1000 μm; then put it into an oven and dry it at 100 °C for 3 h to obtain Zr-doped Cs with a mass ratio of 9 wt% 2 Ag 0.3 Na 0.7 InCl 6Double perovskite / PVDF-based composite piezoelectric film

[0079] Figure 13 This is the Zr-doped Cs prepared in Comparative Example 2 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 Scanning electron microscope (SEM) image of the double perovskite / PVDF-based composite piezoelectric film. It can be seen that the pre-synthesized Zr-doped Cs 2 Ag 0.3 Na 0.7 InCl 6 The double perovskite is unevenly distributed in the film, showing local agglomeration

[0080] Figure 14 This is the Zr-doped Cs prepared using Example 1 and Comparative Example 2 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 Open-circuit voltage and short-circuit current diagrams of the piezoelectric nanogenerator constructed with the double perovskite / PVDF-based composite piezoelectric film. When using the piezoelectric composite film prepared in Comparative Example 2 to construct the piezoelectric nanogenerator, its open-circuit voltage and short-circuit current are 19.V and 4.5 μA·cm -2 respectively, showing poorer performance compared to Example 1

[0081] Figure 15 This is the Zr-doped Cs prepared using Example 1 and Comparative Example 2 of the present invention 2 Ag 0.3 Na 0.7 InCl 6 Stability comparison diagram of the piezoelectric nanogenerator constructed with the double perovskite / PVDF-based composite piezoelectric film. Under the continuous impact of 15 N, the stability of the two piezoelectric nanogenerators was evaluated. The results show that the piezoelectric nanogenerator of Example 1 can still maintain stable electrical output after more than 10,000 cycles, while the V of the piezoelectric nanogenerator of Comparative Example 2 oc begins to decline after only more than 4,000 cycles, highlighting the improved stability of the piezoelectric nanogenerator of Example 1

[0082] In summary, the present invention can not only prepare high-performance PVDF-based composite piezoelectric films by in-situ growth of Zr-doped double perovskite in the PVDF matrix, simplifying the process flow and reducing production costs. At the same time, it can also change the Zr-doped Cs 2 Ag 0.3 Na 0.7 InCl 6The filler weight ratio of the double perovskite induces the transformation of the α-phase to the piezoelectric β-phase in the PVDF matrix, thus enhancing the Zr-doped Cs 2 Ag 0.3 Na 0.7 InCl 6 The piezoelectric properties of the double perovskite / PVDF-based composite piezoelectric film. In addition, the piezoelectric nanogenerator constructed using the prepared composite piezoelectric film not only has excellent piezoelectric characteristics such as open-circuit voltage (V oc ) and short-circuit current density (I sc ), but also has device stability after more than 10,000 cycles, making it have high application prospects in fields such as piezoelectric generators and piezoelectric sensors.

[0083] All aspects, embodiments, and features of the present invention should be considered illustrative in all respects and not limiting of the present invention. The scope of the present invention is only defined by the claims. Without departing from the spirit and scope of the claimed invention, those skilled in the art will appreciate other embodiments, modifications, and uses.

[0084] In the preparation method of the present invention, the order of each step is not limited to the listed order. For those of ordinary skill in the art, without creative efforts, the sequential changes of each step are also within the protection scope of the present invention. In addition, two or more steps or actions can be carried out simultaneously.

[0085] Finally, it should be noted that the specific embodiments described herein are only illustrative of the present invention and do not limit the implementation manners of the present invention. Those skilled in the art of the present invention can make various modifications or supplements to the described specific embodiments or use similar methods to replace them. It is not necessary and impossible to list all implementation manners here. And these obvious changes or variations derived from the essence of the present invention still fall within the protection scope of the present invention. Interpreting them as any additional limitations is contrary to the spirit of the present invention.

Claims

1. An inorganic double perovskite / PVDF-based composite piezoelectric film, characterized in that: The inorganic double perovskite in the composite piezoelectric film is Zr-doped Cs2Ag 0.3 Na 0.7 InCl6 double perovskite, the composite piezoelectric film is in-situ grown Zr-doped Cs2Ag in a PVDF matrix 0.3 Na 0.7 InCl6 double perovskite composite piezoelectric film; Zr-doped Cs2Ag in the composite piezoelectric film 0.3 Na 0.7 The mass percentage of InCl6 double perovskite in the PVDF matrix is ​​3 to 12 wt%.

2. The inorganic double perovskite / PVDF-based composite piezoelectric film according to claim 1, characterized in that: The β-phase content of the inorganic double perovskite / PVDF-based composite piezoelectric film is 80-90wt%; And / or, the piezoelectric coefficient of the inorganic double perovskite / PVDF-based composite piezoelectric film is 14 to 16 pC / N; And / or, the dielectric constant ε value of the inorganic double perovskite / PVDF-based composite piezoelectric film at 30 to 60 kHz is 30 to 45.

3. A method for preparing an inorganic double perovskite / PVDF-based composite piezoelectric film according to any one of claims 1 to 2, characterized in that: The preparation method comprises the following steps: adding zirconium chloride, cesium chloride, silver chloride, sodium chloride, indium chloride and polyvinylidene fluoride into an organic reagent, stirring and dissolving to obtain a precursor solution; coating the precursor solution on a substrate, and drying to obtain Zr-doped Cs2Ag 0.3 Na 0.7 InCl6 double perovskite / PVDF-based composite piezoelectric film.

4. The preparation method according to claim 3, characterized in that: The mass ratio of zirconium chloride, cesium chloride, silver chloride, sodium chloride and indium chloride is (20-100):(30-140):(1-20):(1-20):(20-100).

5. The preparation method according to claim 3, characterized in that: The mass ratio of the total mass of the zirconium chloride, cesium chloride, silver chloride, sodium chloride and indium chloride to polyvinylidene fluoride is (0.01-0.15):

1.

6. The preparation method according to claim 3, characterized in that: The polyvinylidene fluoride is added in the form of powder, and the particle size of the polyvinylidene fluoride powder is 1 to 100 μm.

7. The preparation method according to claim 3, characterized in that: The organic reagent includes one or more of dimethyl sulfoxide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethylformamide, acetone, tetrahydrofuran, and cyclohexanone; And / or, the ratio of the total mass of the zirconium chloride, cesium chloride, silver chloride, sodium chloride, indium chloride and polyvinylidene fluoride to the organic reagent is 1 g: (8-12) mL.

8. The preparation method according to claim 3, characterized in that: The stirring dissolution comprises the following steps: stirring at 60-100° C. and at a speed of 100-600 r / min for 1-10 hours until completely dissolved to obtain a mixed precursor solution; And / or, the precursor solution is uniformly coated on the glass substrate by a doctor blade, and then the glass substrate coated with the precursor solution is transferred to a drying oven for drying; And / or, the coating thickness of the precursor solution is 200-1000 μm, and the coating area is 1-100 cm 2 ; And / or, the drying temperature is 60-180° C., and the drying time is 1-10 hours.

9. A piezoelectric nanogenerator, characterized in that: Its components include an inorganic double perovskite / PVDF-based composite piezoelectric film as described in any one of claims 1-2.

10. The piezoelectric nanogenerator according to claim 9, characterized in that: The piezoelectric nanogenerator has an open circuit voltage of 40 to 50 V and a short circuit current density of 8 to 12 μA·cm -2 The piezoelectric nanogenerator can still maintain stable electrical output after being subjected to a continuous impact force of 10 to 20 N and undergoing 10,000 to 20,000 cycles.

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