A porous PVDF composite material, its nanogenerator and piezoelectric catalysis applications

Abstract

A porous PVDF composite material, its nanogenerator and piezoelectric catalytic applications. The composite material uses barium calcium zirconate titanate ceramic Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O 3 (BCZT) as an inorganic filler, polyethylene glycol (PEG4000) as a plasticizer and pore former, and polyvinylidene fluoride (PVDF) as an organic matrix BCZT / PVDF composite material, which significantly improves the piezoelectric properties of the flexible composite material. The piezoelectric output of the nanogenerator prepared with this flexible composite material can reach 30 V, and the piezoelectric catalytic degradation rate of rhodamine B (RhB) can reach 92%, and the reaction constant can reach 0.01555 min ‑1 . The BCZT ceramic powder is prepared by the sol-gel sintering method, and then the porous BCZT / PVDF composite membrane is prepared by the solution blending-phase separation method. The content of the composite filler is relatively small (less than 12 wt.%), which not only maintains the flexibility of the organic polymer material but also saves economic costs. At the same time, BCZT is an environmentally friendly ferroelectric material, which can effectively alleviate the environmental pollution problem caused by the scrapping of lead-containing piezoelectric ceramic electronic devices such as lead zirconate titanate (PZT).

Description

Technical Field

[0001] The present invention belongs to the technical field of piezoelectric material preparation, and particularly relates to a porous PVDF composite material, its nanogenerator and piezoelectric catalysis application. Background Art

[0002] With the rapid development of miniaturization, portability and intelligence of electronic devices, new electronic devices urgently need energy materials with high performance, light weight and sustainable self-power supply. At present, most of the consumed energy is still polluting materials such as fossil energy, which is not only non-renewable but also has a serious impact on the environment. Moreover, the development and utilization of renewable energy are still lacking. Therefore, the development of new renewable energy materials is a huge challenge faced by sustainable development. Among them, flexible polymer-based piezoelectric materials have good biocompatibility and are considered as the first choice for self-powered energy in new intelligent electronic devices, showing great potential in applications such as wearable devices, prosthetics and healthcare monitoring devices.

[0003] Piezoelectric materials have the ability to convert various mechanical energies in nature into electrical energy. This unique property has enabled them to be applied in many fields such as sensors, nanogenerators, piezoelectric catalysis, biomedicine, etc. With the rapid development of Internet of Things technology and microelectronics technology in recent years, products such as wearable electronic devices and electronic skin have emerged in an endless stream, and the development of flexible electronic devices has been taken seriously by various countries. The manufacturing of new electronic devices is more miniaturized and integrated, which requires existing piezoelectric materials to have better performance. For example, piezoelectric materials must have good flexibility, small volume and light texture. Traditional piezoelectric materials such as PZT obviously no longer meet the requirements of environmental protection and performance. The PVDF material is currently the most prominent polymer piezoelectric polymer, which has good piezoelectric performance, and at the same time has many advantages such as good flexibility, light weight and strong anti-interference ability, and has received extensive attention and research from researchers. In addition, applying periodic ultrasonic waves or vibrations to piezoelectric materials can play a catalytic degradation role. The PVDF piezoelectric membrane catalyst has better reusability, and is simple, efficient and recyclable to process. Therefore, the development of PVDF material devices with high piezoelectric performance is of great significance for the future development of flexible intelligent devices and environmentally friendly materials.

[0004] By optimizing the structure of PVDF-based copolymers and compounding organic-inorganic materials, the stress-induced polarization intensity and remanent polarization intensity can be enhanced, thereby obtaining flexible piezoelectric materials with high piezoelectric output performance, which have great development potential in many piezoelectric fields. Among them, adding inorganic piezoelectric materials to PVDF and its copolymers can make up for the problem of low piezoelectric coefficient of piezoelectric polymers compared with traditional piezoelectric ceramics such as PZT, and greatly improve their piezoelectric performance. Barium calcium zirconate titanate (BCZT) / polyvinylidene fluoride (PVDF) is a composite system that combines high dielectric constant and flexibility. Usually, in order to maintain a high dielectric constant, most studies will increase the mass ratio of inorganic ferroelectric materials. Although this can maintain an ideal dielectric constant, the reduction in the relative content of PVDF greatly affects the flexibility of the capacitor.

[0005] In order to improve flexibility while ensuring high piezoelectric performance, most recent studies have focused on improving the composite system by starting from fillers and preparation processes. Among them, PVDF is used as the preferred material to improve the flexibility of the material, but there is still a large amount of inorganic materials used, which has certain limitations in applications. Summary of the Invention

[0006] The object of the present invention is to provide a preparation method of a porous PVDF composite material, its nano-generator and piezoelectric catalysis applications. The porous flexible film is composed of inorganic fillers, the filler is BCZT piezoelectric ceramic powder, and the pore-forming agent is PEG4000, which can improve flexibility while ensuring piezoelectric performance, improve the compatibility between the filler and the matrix, and enhance piezoelectric performance for further application in nano-generators and piezoelectric catalysis.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A porous BCZT / PVDF flexible composite material, including: BCZT filler is the inorganic filler of the porous composite film, PEG4000 is the plasticizer and pore-forming agent of the porous composite film, and PVDF polymer material is its main matrix; the main matrix is filled with PEG4000 for pore-forming and compounding, and then compounded with BCZT inorganic filler; calculated by the percentage mass fraction of filling, the filling amount of PEG4000 is 2wt.%, and the filling amount of BCZT inorganic filler is 2-12wt.%.

[0009] Optionally, the filling amount of the BCZT inorganic filler is 2, 4, 6, 8, 10 or 12wt.%.

[0010] Optionally, the thickness of the porous BCZT / PVDF flexible composite material is 15-100um.

[0011] A method for preparing a porous BCZT / PVDF composite material, wherein the porous BCZT / PVDF flexible composite material is any porous BCZT / PVDF composite material described in the present invention; the preparation method comprises:

[0012] Step 1: Preparation of BCZT powder by sol-gel-sintering method: Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O 3 The chemical composition of BCZT filler is to mix barium acetate, calcium acetate and water in a stoichiometric ratio to obtain solution A; at the same time, appropriate amounts of acetic acid and ethanol are added to Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O 3 The stoichiometric ratio of butyl titanate, zirconium n-butoxide and acetylacetone in the BCZT filler is mixed to obtain solution B; solution A is mixed with solution B to prepare BCZT gel, which is dried and sintered at a high temperature, and then ground to obtain BCZT piezoelectric ceramic powder;

[0013] Step 2: preparing a porous PVDF film by a phase separation method: dissolving PEG4000 and PVDF in an organic solvent at a fixed mass fraction ratio to obtain a PVDF film casting solution, casting the film casting solution onto a glass sheet, drying it in a coagulation bath, and then quenching and peeling it off to obtain a porous PVDF film;

[0014] Step 3: Prepare porous BCZT / PVDF flexible composite film by solution blending and phase separation method: firstly, dissolve BCZT inorganic filler in organic solvent and compound with PVDF casting solution, and then dry in coagulation bath and quench and peel off to obtain porous BCZT / PVDF flexible composite film material.

[0015] Optionally, the step three specifically includes:

[0016] 3.1. Dissolve PEG4000 and PVDF powder in an organic solvent to obtain a PVDF film casting solution;

[0017] 3.2. Add the BCZT piezoelectric ceramic powder prepared in step 1 to the PVDF film casting solution and stir evenly to obtain a porous BCZT / PVDF composite material; optionally, in 3.1, the organic solvent is N,N-dimethylformamide, the dissolution temperature is room temperature, and the dissolution time is 6 to 7.5 hours.

[0018] Optionally, the stirring temperature in 3.2 is room temperature and the stirring time is 6 hours.

[0019] A porous BCZT / PVDF flexible composite material, and the porous BCZT / PVDF flexible composite film is composed of the porous BCZT / PVDF material described in any one of the present invention.

[0020] Specifically, it includes: BCZT, PVDF, and PEG4000 materials are dissolved in an organic solvent and then cast or coated into a film to form a porous BCZT / PVDF flexible film.

[0021] Optionally, specifically includes:

[0022] Step 1: Preparation of BCZT powder by sol-gel-sintering method: Mix the formulated amounts of barium acetate, calcium acetate, and water to obtain solution A; mix the formulated amounts of acetic acid, ethanol, tetrabutyl titanate, zirconium n-butoxide, and acetylacetone to obtain solution B; mix solution A and solution B to prepare a BCZT gel, dry it, sinter it at a high temperature, and grind it to obtain BCZT piezoelectric ceramic powder.

[0023] Step 2: Preparation of porous PVDF film by phase separation method: Dissolve PEG4000 in PVDF according to a fixed mass fraction ratio in an organic solvent to obtain a PVDF casting solution, cast the casting solution onto a glass sheet, perform coagulation bath drying treatment, and then quench and peel to obtain a porous PVDF film.

[0024] Step 3: Preparation of porous BCZT / PVDF flexible composite film by solution blending method and phase separation method: First, dissolve BCZT inorganic filler in an organic solvent and compound it with the PVDF casting solution, and then perform coagulation bath drying treatment and quench and peel to obtain a porous BCZT / PVDF flexible composite film material.

[0025] A flexible nanogenerator is prepared by coating an electrode on the surface of the porous BCZT / PVDF flexible film described in the present invention.

[0026] A thin-film piezoelectric catalyst is prepared by sputtering gold on the surface of the porous BCZT / PVDF flexible film described in the present invention.

[0027] The beneficial effects of the present invention:

[0028] The method of the present invention prepares barium calcium zirconate titanate Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9The BCZT / PVDF composite material with O(BCZT) as the inorganic filler, polyethylene glycol (PEG4000) as the plasticizer and pore-forming agent, and polyvinylidene fluoride (PVDF) as the organic matrix significantly improves the piezoelectric properties of the flexible composite material. The optimized piezoelectric output of this material can reach 30 V, the piezoelectric catalytic degradation rate for rhodamine B (RhB) can reach 92%, and the reaction constant can reach 0.01555 min -1 , furthermore, based on this porous BCZT / PVDF composite material, only a filling amount of less than 12 wt.% is required. Combined with PVDF, excellent flexible nanogenerators and thin-film piezoelectric catalysts can be prepared with additional electrodes. While maintaining the flexibility of the material, the economic cost is saved. At the same time, BCZT is an environmentally friendly ferroelectric material, which can effectively alleviate the environmental pollution problem caused by the scrapping of lead-containing piezoelectric ceramic electronic devices. Description of the Drawings

[0029] Figure 1 X-ray diffraction patterns of the porous BCZT / PVDF flexible composite films prepared in Examples 2-7;

[0030] Figure 2 Scanning electron micrographs of the porous BCZT / PVDF flexible composite films prepared in Examples 2-7

[0031] Figure 3 Piezoelectric output performance diagrams of the porous BCZT / PVDF flexible composite films prepared in Examples 2-7;

[0032] Figure 4 Piezoelectric catalytic performance diagrams of the porous BCZT / PVDF flexible composite films prepared in Examples 2-7; Detailed Description of the Invention

[0033] The following further elaborates on the present invention in conjunction with the examples.

[0034] The porous PVDF composite material of the present invention and its applications in nanogenerators and piezoelectric catalysis. The porous BCZT / PVDF flexible film is specifically composed of a composite of an inorganic filler and a pore-forming agent material, specifically a barium calcium zirconate titanate (BCZT) / polyvinylidene fluoride (PVDF) composite material of polyethylene glycol 4000 (PEG4000). In the research of flexible piezoelectric materials, the inorganic filler is the source of their high piezoelectric coefficient. BCZT is a high-dielectric lead-free material. By introducing Zr 4+ and Ca 2+ into BaTiO 3 , in the crystal lattice, Zr 4+ replaces part of Ti 4+ , and Ca 2+ replaces part of Ba 2+, the dielectric peak at the Curie point broadens and extends to near room temperature, thereby making its dielectric constant higher than that of BaTiO 3 higher and the capacitance temperature coefficient lower, which can better meet the requirements of electronic devices. However, as the demand for flexibility in electronic devices increases, industrial applications often involve composites of polymer organic molecular materials and inorganic materials. However, the piezoelectric properties of polymer materials are relatively low, which limits the application of materials in terms of performance. Therefore, in order to improve both the piezoelectric coefficient and flexibility, the present invention combines BCZT with good ferroelectricity and porous PVDF through sol-gel sintering, phase separation, and solution co-blending and casting methods to improve the compatibility between the filler and the matrix and enhance the piezoelectric properties for further application in flexible composite electronic devices.

[0035] The porous BCZT / PVDF composite material of the present invention includes: BCZT filler as the inorganic filler of the porous composite membrane, PEG4000 as the plasticizer and pore-forming agent of the porous composite membrane, and PVDF polymer material as its main matrix; the main matrix is filled with PEG4000 for pore-forming and composite, and then compounded with BCZT inorganic filler; calculated by the mass fraction of filling, the filling amount of PEG4000 is 2 wt.%, and the filling amount of BCZT inorganic filler is 2 - 12 wt.%. Specifically, the filling amount of BCZT inorganic filler is 2, 4, 6, 8, 10, or 12 wt.%, and the thickness of the porous BCZT / PVDF flexible composite material is 15 - 100 μm.

[0036] Barium calcium zirconate titanate Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O 3 (BCZT) as the inorganic filler, polyethylene glycol (PEG4000) as the plasticizer and pore-forming agent, and polyvinylidene fluoride (PVDF) as the organic matrix of the BCZT / PVDF composite material significantly improves the piezoelectric properties of the flexible composite material. The piezoelectric output of the nanogenerator prepared from this flexible composite material can reach 30 V, and the piezoelectric catalytic degradation rate for rhodamine B (RhB) can reach 92%, and the reaction constant can reach 0.01555 min -1 , further, based on this BCZT / PVDF porous composite material, only a filling amount of less than 12 wt.% is required, combined with PVDF, to prepare flexible nanogenerators and thin-film piezoelectric catalysts with excellent performance by attaching electrodes. While maintaining the flexibility of the material, the economic cost is saved. At the same time, BCZT is an environmentally friendly ferroelectric material, which can effectively alleviate the environmental pollution problem caused by the scrapping of lead-containing piezoelectric ceramic electronic devices.

[0037] The preparation method of the porous BCZT / PVDF flexible film includes the following steps:

[0038] Step 1. Preparation of BCZT powder by sol-gel-sintering method: Mix barium acetate, calcium acetate and water in the formula amount to obtain solution A; mix acetic acid, ethanol, tetrabutyl titanate, zirconium n-butoxide and acetylacetone in the formula amount to obtain solution B; mix solution A and solution B to prepare BCZT gel, dry it and sinter it at high temperature, and grind it to obtain BCZT piezoelectric ceramic powder;

[0039] Step 2. Preparation of porous PVDF film by phase separation method: Dissolve PEG4000 in PVDF in a fixed mass fraction ratio in an organic solvent to obtain a PVDF casting solution, cast the casting solution onto a glass sheet, perform coagulation bath drying treatment and then quench and peel to obtain a porous PVDF film;

[0040] Step 3. Preparation of porous BCZT / PVDF flexible composite film by solution blending method and phase separation method: First dissolve BCZT inorganic filler in an organic solvent and compound it with the PVDF casting solution, and perform coagulation bath drying treatment and then quench and peel to obtain a porous BCZT / PVDF flexible composite film material.

[0041] In Step 1, in the prepared porous BCZT / PVDF composite material, control the separation of positive and negative charges under stress, enhance the charge density, and improve the piezoelectric performance.

[0042] The porous BCZT / PVDF flexible film can be obtained by casting or coating the BCZT / PVDF material dissolved in an organic solvent into a film to form a porous BCZT / PVDF flexible film; specifically, in Step 3, dissolve PEG4000 and PVDF powder in an organic solvent to obtain a PVDF casting solution; add the BCZT piezoelectric ceramic powder prepared in Step 1 to the PVDF casting solution and stir evenly to obtain a porous BCZT / PVDF composite material.

[0043] The preparation method of a flexible nanogenerator includes: coating an electrode on the surface of the porous BCZT / PVDF flexible film to prepare a flexible nanogenerator, and the electrode material is one or a mixture of conductive silver, gold powder, copper foil or aluminum foil, and the bonding method of the electrode material is one of vacuum coating method, magnetron sputtering method, spraying method or dry pressing method.

[0044] The preparation method of a thin-film piezoelectric catalyst includes: sputtering gold on the surface of the porous BCZT / PVDF flexible film to prepare a thin-film piezoelectric catalyst.

[0045] The technical solution of the present invention will be described in detail below in conjunction with specific embodiments. It should be clear that the materials used in the following experiments are all commercially available unless otherwise specified; the methods used are all common experimental or testing methods in the art unless otherwise specified.

[0046] Example 1:

[0047] The method for preparing the inorganic filler BCZT piezoelectric ceramic powder comprises the following steps:

[0048] Dissolve 6.5 g of Ba(CH 3 COO) 2 and 0.79 g of Ca(CH 3 COO) 2 in 15 ml of deionized water, add it to a mixed solution of 5 ml of acetic acid and 33 ml of ethanol to dissolve 9.19 g of Ti(OC 4 H 9 ) 4 and 1.44 g of C 16 H 36 O 4 Zr, and add 20 drops of acetylacetone. After sufficient stirring, a uniform BCZT gel is obtained. Dry and grind the gel, and then perform high-temperature sintering in a muffle furnace. After drying and grinding, BCZT powder is obtained.

[0049] Example 2:

[0050] Add the BCZT powder in Example 1 to 6 ml of N-N-dimethylformamide (DMF) according to the filling mass fraction ratio of 2 wt.%. After sufficient ultrasonic stirring, make the BCZT uniformly dispersed in the DMF. Then add 0.45 g of PVDF and 0.01253 g of PEG4000 to the above mixed solution. After sufficient ultrasonic stirring again, a casting solution is obtained. Cast it on a glass sheet, dry, quench, peel it off, and perform vacuum ion sputtering on its upper and lower surfaces to make gold electrodes with a diameter of 2 mm to obtain a porous BCZT / PVDF flexible composite film (BCZT / PVDF-2).

[0051] The XRD of the BCZT / PVDF-2 composite film is as Figure 1 shown, and the SEM is as Figure 2 shown. The filler is uniformly dispersed in the PVDF, and there is good interfacial compatibility between the matrix and the filler. The output performance of the nanogenerator prepared from this flexible composite film can reach 2 V, as Figure 3 shown. The catalytic efficiency of the prepared piezoelectric catalyst can reach 24%, and the reaction constant can reach 0.00167 min -1 . In the following experiments, unless otherwise specified in terms of dosage, the addition amount and concentration of substances refer to Example 2.

[0052] Example 3:

[0053] The BCZT powder in Example 1 was added to N,N-dimethylformamide (DMF) at a filling mass fraction ratio of 4 wt.%, and after sufficient ultrasonic stirring, the BCZT was uniformly dispersed in the DMF. Then PVDF and PEG4000 were added to the above mixed solution, and after sufficient ultrasonic stirring again, a casting solution was obtained. It was cast onto a glass sheet, dried, quenched, peeled off, and gold electrodes with a diameter of 2 mm were sputtered on its upper and lower surfaces to prepare a porous BCZT / PVDF flexible composite film (BCZT / PVDF-4).

[0054] The XRD of the BCZT / PVDF-4 composite film is as Figure 1 shown, and the SEM is as Figure 2 shown. The filler is uniformly dispersed in the PVDF, and there is good interfacial compatibility between the matrix and the filler. The output performance of the nanogenerator prepared from this flexible composite film can reach 2 V, as Figure 3 shown. The catalytic efficiency of the prepared piezoelectric catalyst can reach 30%, and the reaction constant can reach 0.00222 min -1 , as Figure 4 shown.

[0055] Example 4:

[0056] The BCZT powder in Example 1 was added to N,N-dimethylformamide (DMF) at a filling mass fraction ratio of 6 wt.%, and after sufficient ultrasonic stirring, the BCZT was uniformly dispersed in the DMF. Then PVDF and PEG4000 were added to the above mixed solution, and after sufficient ultrasonic stirring again, a casting solution was obtained. It was cast onto a glass sheet, dried, quenched, peeled off, and gold electrodes with a diameter of 2 mm were sputtered on its upper and lower surfaces to prepare a porous BCZT / PVDF flexible composite film (BCZT / PVDF-6).

[0057] The XRD of the BCZT / PVDF-6 composite film is as Figure 1 shown, and the SEM is as Figure 2 shown. The filler is uniformly dispersed in the PVDF, and there is good interfacial compatibility between the matrix and the filler. The output performance of the nanogenerator prepared from this flexible composite film can reach 6 V, as Figure 3 shown. The catalytic efficiency of the prepared piezoelectric catalyst can reach 33%, and the reaction constant can reach 0.00253 min -1 , as Figure 4 shown.

[0058] Example 5:

[0059] The BCZT powder in Example 1 was added to N,N-dimethylformamide (DMF) at a filling mass fraction ratio of 8 wt.%. After sufficient ultrasonic stirring, the BCZT was uniformly dispersed in the DMF. Then, PVDF and PEG4000 were added to the above mixed solution, and after sufficient ultrasonic stirring again, a casting solution was obtained. It was cast onto a glass sheet, dried, quenched, peeled off, and gold electrodes with a diameter of 2 mm were vacuum ion-sputtered on its upper and lower surfaces to obtain a porous BCZT / PVDF flexible composite film (BCZT / PVDF-8).

[0060] The XRD of the BCZT / PVDF-6 composite film is as Figure 1 shown, and the SEM is as Figure 2 shown. The filler is uniformly dispersed in the PVDF, and the matrix and the filler have good interfacial compatibility. The output performance of the nanogenerator prepared from this flexible composite film can reach 15 V, as Figure 3 shown. The catalytic efficiency of the prepared piezoelectric catalyst can reach 56%, and the reaction constant can reach 0.00496 min -1 as Figure 4 shown.

[0061] Example 6:

[0062] The BCZT powder in Example 1 was added to N,N-dimethylformamide (DMF) at a filling mass fraction ratio of 10 wt.%. After sufficient ultrasonic stirring, the BCZT was uniformly dispersed in the DMF. Then, PVDF and PEG4000 were added to the above mixed solution, and after sufficient ultrasonic stirring again, a casting solution was obtained. It was cast onto a glass sheet, dried, quenched, peeled off, and gold electrodes with a diameter of 2 mm were vacuum ion-sputtered on its upper and lower surfaces to obtain a porous BCZT / PVDF flexible composite film (BCZT / PVDF-10).

[0063] The XRD of the BCZT / PVDF-6 composite film is as Figure 1 shown, and the SEM is as Figure 2 shown. The filler is uniformly dispersed in the PVDF, and the matrix and the filler have good interfacial compatibility. The output performance of the nanogenerator prepared from this flexible composite film can reach 30 V, as Figure 3 shown. The catalytic efficiency of the prepared piezoelectric catalyst can reach 92%, and the reaction constant can reach 0.01555 min -1 as Figure 4 shown.

[0064] Example 7:

[0065] The BCZT powder in Example 1 was added to N,N-dimethylformamide (DMF) at a filling mass fraction ratio of 12 wt.%. After sufficient ultrasonic stirring, BCZT was uniformly dispersed in DMF. Then, PVDF and PEG4000 were added to the above mixed solution, and a casting solution was obtained after sufficient ultrasonic stirring again. It was cast onto a glass sheet, dried, quenched, peeled off, and gold electrodes with a diameter of 2 mm were vacuum ion sputtered on its upper and lower surfaces to prepare a porous BCZT / PVDF flexible composite film (BCZT / PVDF-12).

[0066] The XRD of the BCZT / PVDF-12 composite film is as Figure 1 shown, and the SEM is as Figure 2 shown. The filler is uniformly dispersed in PVDF, and there is good interfacial compatibility between the matrix and the filler. The output performance of the nanogenerator prepared from this flexible composite film can reach 15 V, as Figure 3 shown. The catalytic efficiency of the prepared piezoelectric catalyst can reach 55%, and the reaction constant can reach 0.00479 min -1 , as Figure 4 shown.

[0067] The best embodiments are preferentially and elaborately described above in combination with the accompanying drawings, which are not used to limit the present invention. For the various specific technical features described above, they can be combined in any suitable form without contradiction, and the present invention will not be elaborated one by one. Any person skilled in the art can, without departing from the scope of the technical solution, take means such as arbitrary combination or equivalent replacement of the technical solution, or make simple modifications or decorations, which do not affect the essence of its technical solution and still fall within the protection scope of the technical solutions represented by the embodiments of the present invention.

Claims

1. A porous BCZT / PVDF flexible composite material, characterized in that, it includes: Using barium calcium zirconate titanate Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O 3 (BCZT) ceramic filler as the inorganic filler of the porous composite membrane, PEG4000 as the plasticizer and pore former of the porous composite membrane, and PVDF polymer material as the main matrix; Pore-forming and compounding the main matrix by filling PEG4000, and then compounding with BCZT inorganic filler; Calculated by the mass percentage of filling, the filling amount of PEG4000 is 2wt.%, and the filling amount of BCZT inorganic filler is 2-12wt.%.

2. The porous BCZT / PVDF flexible composite material according to claim 1, characterized in that, the filling amount of the BCZT inorganic filler is 2, 4, 6, 8, 10 or 12wt.%; the thickness of the flexible composite material is 15-100μm.

3. A method for preparing a composite film of a porous BCZT / PVDF flexible composite material, characterized in that, the composite material is any one of the porous BCZT / PVDF flexible composite materials in claims 1-2, and the preparation of the composite film includes the following steps: Step 1. Preparation of BCZT powder by sol-gel-sintering method: According to the stoichiometric ratio of chemical composition in Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O 3 (BCZT) filler, barium acetate, calcium acetate and water are mixed to obtain solution A; at the same time, appropriate amounts of acetic acid and ethanol are added to Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O 3 (BCZT) filler, and tetrabutyl titanate, zirconium n-butoxide and acetylacetone in the stoichiometric ratio of chemical composition are mixed to obtain solution B; solution A and solution B are mixed to prepare a gel, which is dried and then sintered at high temperature, and ground to obtain BCZT piezoelectric ceramic powder; Step two: Prepare a PVDF casting solution: Dissolve PEG4000 and PVDF in an organic solvent according to a fixed mass fraction ratio to obtain a PVDF casting solution; Step three: Prepare a porous BCZT / PVDF flexible composite film by solution blending method and phase separation method: Disperse the BCZT piezoelectric ceramic powder prepared in step one in an organic solvent, and then add it to the PVDF casting solution prepared in step two for mixing, stir evenly, cast or coat into a film, and obtain a porous BCZT / PVDF flexible composite film material after drying treatment and quenching and peeling.

4. The method for preparing a composite film of a porous BCZT / PVDF flexible composite material according to claim 3, characterized in that, the organic solvent in step one is N,N-dimethylformamide, the dissolution temperature is room temperature, and the dissolution time is 6-7.5h.

5. The method for preparing a composite film of a porous BCZT / PVDF flexible composite material according to claim 3, characterized in that, the stirring temperature in step three is room temperature, and the stirring time is 6h.

6. A nanogenerator, characterized in that, coat electrodes on the surface of the porous BCZT / PVDF flexible composite film material obtained by the method in claim 3 to prepare a flexible nanogenerator.

7. A thin-film piezoelectric catalyst, characterized in that, sputter gold on the surface of the porous BCZT / PVDF flexible composite film material obtained by the method in claim 3 to prepare a thin-film piezoelectric catalyst.

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