Preparation method of inorganic single crystal, preparation method of composite film and application
阅读说明：本技术 一种无机单晶的制备方法、复合膜的制备方法及应用 (Preparation method of inorganic single crystal, preparation method of composite film and application ) 是由 黎明 黎婵 杨子欣 吴奕纯 于 2021-06-02 设计创作，主要内容包括：本发明提供了一种无机单晶的制备方法、复合膜的制备方法及应用。该无机单晶的制备方法为：将钠盐溶于水中,得到第一溶液；将六氯三聚磷腈加入至有机溶剂中,溶解后得到六氯三聚磷腈溶液；将第一溶液加入至六氯三聚磷腈溶液中,静置后得到单晶；或,将钠盐与钾盐均溶于水中,得到第二溶液；将六氯三聚磷腈加入至有机溶剂中,溶解后得到六氯三聚磷腈溶液；将第二溶液加入至六氯三聚磷腈溶液中,静置后得到单晶。本发明采用含有钠盐的第一溶液或含有钾盐或钠盐的第二溶液,与六氯三聚磷腈溶液反应,最终制备得到单晶,制备得到的单晶均不含重金属元素,制备过程环保,工艺简单。利用该单晶制备得到的复合膜制成的压电器件具有较好的压电输出性能。(The invention provides a preparation method of an inorganic single crystal, a preparation method of a composite film and application. The preparation method of the inorganic single crystal comprises the following steps: dissolving sodium salt in water to obtain a first solution; adding hexachlorotriphosphazene into an organic solvent, and dissolving to obtain a hexachlorotriphosphazene solution; adding the first solution into a hexachlorotriphosphazene solution, and standing to obtain a single crystal; or dissolving the sodium salt and the potassium salt in water to obtain a second solution; adding hexachlorotriphosphazene into an organic solvent, and dissolving to obtain a hexachlorotriphosphazene solution; and adding the second solution into the hexachlorotriphosphazene solution, and standing to obtain the single crystal. According to the invention, the first solution containing sodium salt or the second solution containing potassium salt or sodium salt reacts with the hexachlorotriphosphazene solution to finally prepare the single crystal, the prepared single crystal does not contain heavy metal elements, the preparation process is environment-friendly, and the process is simple. A piezoelectric device made of the composite film prepared by the single crystal has better piezoelectric output performance.)
1. A method for preparing an inorganic single crystal, comprising the steps of:
dissolving sodium salt in water to obtain a first solution;
adding hexachlorotriphosphazene into a first organic solvent, and dissolving to obtain a hexachlorotriphosphazene solution;
adding the first solution into a hexachlorotriphosphazene solution, and standing to obtain Na3(PO2NH)3·4H2O single crystal;
or dissolving the sodium salt and the potassium salt in water to obtain a second solution;
adding hexachlorotriphosphazene into a first organic solvent, and dissolving to obtain a hexachlorotriphosphazene solution;
adding the second solution into the hexachlorotriphosphazene solution, and standing to obtain KNa2(PO2NH)3·2H2And (4) O single crystal.
2. The method of producing an inorganic single crystal according to claim 1, wherein in the step of dissolving the sodium salt in water, the sodium salt is an alkaline sodium salt;
in the step of dissolving both sodium salt and potassium salt in water, the sodium salt is alkaline sodium salt, and the potassium salt is non-alkaline potassium salt; or the potassium salt is alkaline potassium salt, and the sodium salt is non-alkaline sodium salt.
3. The method for producing an inorganic single crystal according to claim 1, wherein the first solution is added to the solution of hexachlorotriphosphazene, and Na is obtained after leaving to stand3(PO2NH)3·4H2O single crystal; adding the second solution into the hexachlorotriphosphazene solution, and standing to obtain KNa2(PO2NH)3·2H2O single crystal; wherein, the standing specifically comprises the following steps: standing for 6-24 h at 15-50 ℃.
4. A method for producing an inorganic single crystal according to claim 1, wherein the molar ratio of the sodium salt to the hexachlorotriphosphazene in the first solution is (3-6): 1.
5. A method for producing an inorganic single crystal according to claim 1, wherein the molar ratio of the sodium salt to the potassium salt in the second solution is (1 to 2):1, and the molar ratio of the potassium salt to the hexachlorotriphosphazene in the second solution is (3 to 6): 1.
6. A preparation method of a composite film is characterized by comprising the following steps:
na produced by the production method according to any one of claims 1 to 53(PO2NH)3·4H2O single crystal or KNa2(PO2NH)3·2H2Adding O single crystal into a second organic solvent to obtain a dispersion liquid;
adding a polymer into the dispersion liquid, and stirring to obtain a polymer dispersion liquid;
and (3) taking the polymer dispersion liquid as a spinning solution, and preparing the composite membrane by using an electrostatic spinning process.
7. The method for preparing the composite membrane according to claim 6, wherein a polymer is added to the dispersion, and the mixture is stirred at 50 to 70 ℃ for 10 to 15 hours to obtain a polymer dispersion, wherein the polymer comprises one of PVDF, a copolymer of PVDF, polylactic acid and polyamide.
8. The method for preparing the composite membrane according to claim 6, wherein the polymer dispersion liquid is used as a spinning solution, and the composite membrane prepared by an electrostatic spinning process is specifically as follows: and transferring the polymer dispersion liquid to a needle head of an electrostatic spinning device, spinning for 1-3 h at the electric field intensity of 0.5-1.5 MV/m and the receiving roller speed of 2500-3000 rpm to obtain a wet film, and drying the wet film to obtain the composite film.
9. A method of making a composite membrane according to claim 6 wherein Na is present in the polymer dispersion3(PO2NH)3·4H2O single crystal or KNa2(PO2NH)3·2H2The mass ratio of the O single crystal to the polymer is 1 (2-10).
10. Use of the composite film prepared by the preparation method according to any one of claims 6 to 9 in preparation of energy collection devices and electric energy storage devices.
Technical Field
The invention relates to the technical field of functional materials, in particular to a preparation method of an inorganic single crystal, a preparation method of a composite film and application.
Background
In recent years, various materials having piezoelectric effect, such as inorganic piezoelectric single crystals (e.g., zinc oxide and zinc sulfide), piezoelectric ceramics (e.g., lead zirconate titanate, barium titanate, sodium niobate), piezoelectric polymers (e.g., polyvinylidene fluoride and copolymers thereof, polyamide), and the like, have been developed and widely used in the fields of drivers, sensors, self-powered systems, energy harvesting, and the like. Piezoelectric single crystals and piezoelectric ceramics generally have a high d33However, the material is brittle and fragile, has poor processability, is rich in heavy metal elements such as lead, barium and the like, and greatly limits the application of the material in the biological field.
Because the existing piezoelectric single crystal contains heavy metal elements and is not beneficial to environmental protection, a new preparation method of the inorganic single crystal is needed to be provided.
Disclosure of Invention
In view of the above, the present invention provides a method for preparing an inorganic single crystal, a method for preparing a composite film, and applications thereof, so as to solve or partially solve the technical problems in the prior art.
In a first aspect, the present invention provides a method for preparing an inorganic single crystal, comprising the steps of:
dissolving sodium salt in water to obtain a first solution;
adding hexachlorotriphosphazene into a first organic solvent, and dissolving to obtain a hexachlorotriphosphazene solution;
adding the first solution into a hexachlorotriphosphazene solution, and standing to obtain Na3(PO2NH)3·4H2O single crystal;
or dissolving the sodium salt and the potassium salt in water to obtain a second solution;
adding hexachlorotriphosphazene into a first organic solvent, and dissolving to obtain a hexachlorotriphosphazene solution;
adding the second solution into the hexachlorotriphosphazene solution, and standing to obtain KNa2(PO2NH)3·2H2And (4) O single crystal.
Preferably, in the method for preparing an inorganic single crystal, in the step of dissolving the sodium salt in water, the sodium salt is an alkaline sodium salt;
in the step of dissolving both sodium salt and potassium salt in water, the sodium salt is alkaline sodium salt, and the potassium salt is non-alkaline potassium salt; or the potassium salt is alkaline potassium salt, and the sodium salt is non-alkaline sodium salt.
Preferably, the preparation method of the inorganic single crystal comprises the steps of adding the first solution into a hexachlorotriphosphazene solution, standing to obtain Na3(PO2NH)3·4H2O single crystal; adding the second solution into the hexachlorotriphosphazene solution, and standing to obtain KNa2(PO2NH)3·2H2O single crystal; wherein, the standing specifically comprises the following steps: standing for 6-24 h at 15-50 ℃.
Preferably, in the method for preparing the inorganic single crystal, the molar ratio of the sodium salt to the hexachlorotriphosphazene in the first solution is (3-6): 1.
Preferably, in the method for preparing the inorganic single crystal, the molar ratio of the sodium salt to the potassium salt in the second solution is (1-2): 1, and the molar ratio of the potassium salt to the hexachlorotriphosphazene in the second solution is (3-6): 1.
In a second aspect, the present invention also provides a method for preparing a composite film, comprising the steps of:
na prepared by the preparation method3(PO2NH)3·4H2O single crystal or KNa2(PO2NH)3·2H2Adding O single crystal into a second organic solvent to obtain a dispersion liquid;
adding a polymer into the dispersion liquid, and stirring to obtain a polymer dispersion liquid;
and (3) taking the polymer dispersion liquid as a spinning solution, and preparing the composite membrane by using an electrostatic spinning process.
Preferably, in the preparation method of the composite membrane, a polymer is added into the dispersion liquid, and the mixture is stirred for 10-15 hours at 50-70 ℃ to obtain a polymer dispersion liquid, wherein the polymer comprises one of PVDF, a copolymer of PVDF, water-soluble cellulose, polylactic acid and polyimide.
Preferably, the preparation method of the composite membrane, which takes the polymer dispersion liquid as the spinning solution and utilizes the electrostatic spinning process to prepare the composite membrane, specifically comprises the following steps: and transferring the polymer dispersion liquid to a needle head of an electrostatic spinning device, spinning for 1-3 h at the electric field intensity of 0.5-1.5 MV/m and the receiving roller speed of 2500-3000 rpm to obtain a wet film, and drying the wet film to obtain the composite film.
Preferably, the preparation method of the composite membrane is Na in polymer dispersion liquid3(PO2NH)3·4H2O single crystal or KNa2(PO2NH)3·2H2The mass ratio of the O single crystal to the polymer is 1 (2-10).
In a third aspect, the invention further provides an application of the composite film prepared by the preparation method in preparation of energy collection devices and electric energy storage devices.
Compared with the prior art, the preparation method of the inorganic single crystal and the preparation method and application of the composite film have the following beneficial effects:
(1) the preparation method of the inorganic single crystal adopts the first solution containing sodium salt or the second solution containing potassium salt or sodium salt to react with the hexachlorotriphosphazene solution to finally prepare Na3(PO2NH)3·4H2O single crystal or KNa2(PO2NH)3·2H2The O single crystal, the preparation process and the prepared single crystal do not contain heavy metal elements, the preparation process is environment-friendly, and the process is simple;
(2) the preparation method of the composite membrane of the invention is to mix Na3(PO2NH)3·4H2O single crystal and KNa2(PO2NH)3·2H2The composite film with both piezoelectric activity and flexibility can be prepared after the O single crystal is respectively compounded with the polymer, the piezoelectric device prepared by the composite film has better piezoelectric output performance, and the device can be used as an energy collecting device, and the collected electric energy can be directly stored in a capacitor, which indicates that the device is used for energy collection and electricity collectionCan be stored and used and has excellent application prospect in the fields of storage, use and the like.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.
FIG. 1 shows Na prepared in example 1 of the present invention3(PO2NH)3·4H2An appearance morphology diagram of O single crystal;
FIG. 2 shows Na prepared in example 1 of the present invention3(PO2NH)3·4H2Optical microscopy of O single crystals;
FIG. 3 is a surface topography of the PNONa-PVDF composite membrane prepared in example 1 of the present invention;
FIG. 4 is a graph of the open circuit voltage of the PNONa-PVDF device;
FIG. 5 is a graph of the piezoelectric output performance of a PNONa-PVDF device under different applied loads;
FIG. 6 is a schematic diagram of the energy collected by the PNONa-PVDF device to light up an LED lamp;
FIG. 7 shows KNa obtained in example 2 of the present invention2(PO2NH)3·2H2An appearance morphology diagram of O single crystal;
FIG. 8 shows KNa obtained in example 2 of the present invention2(PO2NH)3·2H2Optical microscopy of O single crystals;
FIG. 9 is a surface topography of the PNONaK-PVDF composite membrane prepared in example 2 of the present invention;
FIG. 10 is a graph of the open circuit voltage of the PNONaK-PVDF device;
FIG. 11 is a graph of the piezoelectric output performance of the PNONAK-PVDF device under different applied loads;
FIG. 12 is a PNONaK-PVDF device stability test chart;
FIG. 13 is a graph of the energy harvesting effect of PNONAK-PVDF devices on human gait;
FIG. 14 is a graph of the energy harvesting effect of PNONAK-PVDF devices on human running;
FIG. 15 shows Na prepared in examples 3 to 63(PO2NH)3·4H2An appearance morphology diagram of O single crystal;
FIG. 16 shows Na prepared in examples 7 to 93(PO2NH)3·4H2An appearance morphology diagram of O single crystal;
FIG. 17 shows KNa obtained in examples 10 to 132(PO2NH)3·2H2Appearance morphology diagram of O single crystal.
Detailed Description
In the following, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
The embodiment of the application provides a preparation method of an inorganic single crystal, which comprises the following steps:
s11, dissolving the sodium salt in water to obtain a first solution;
s12, adding hexachlorotriphosphazene into an organic solvent, and dissolving to obtain a hexachlorotriphosphazene solution;
s13, adding the first solution into a hexachlorotriphosphazene solution, and standing to obtain Na3(PO2NH)3·4H2O single crystal;
or, a method for preparing an inorganic single crystal, comprising the steps of:
s21, dissolving the sodium salt and the potassium salt in water to obtain a second solution;
s22, adding hexachlorotriphosphazene into the first organic solvent, and dissolving to obtain a hexachlorotriphosphazene solution;
s23, mixingAdding the second solution into the hexachlorotriphosphazene solution, and standing to obtain KNa2(PO2NH)3·2H2And (4) O single crystal.
In the embodiment of the present invention, the first organic solvent is a solvent that can dissolve hexachlorotriphosphazene and is miscible with water, for example, the first organic solvent may be DMF, NMP, DMSO, dioxane, or the like.
In some embodiments, the step of dissolving the sodium salt in water is performed by dissolving the sodium salt in water, wherein the sodium salt is alkaline sodium salt, and the sodium salt can be NaOH or Na2CO3、NaHCO3And the like.
In some embodiments, in the step of dissolving both the sodium salt and the potassium salt in water, the sodium salt is a basic sodium salt and the potassium salt is a non-basic potassium salt; or the potassium salt is alkaline potassium salt, and the sodium salt is non-alkaline sodium salt. Specifically, the alkaline sodium salt is NaOH or Na2CO3、NaHCO3Etc., the non-alkaline sodium salt is NaCl, Na2SO4、NaNO3Etc., the alkaline potassium salt is KOH or K2CO3、KHCO3Etc., the non-basic potassium salt is KCl, K2SO4、KNO3And the like.
In some embodiments, the first solution is added to the solution of hexachlorotriphosphazene and Na is obtained after standing3(PO2NH)3·4H2O single crystal; adding the second solution into the hexachlorotriphosphazene solution, and standing to obtain KNa2(PO2NH)3·2H2O single crystal; wherein, the standing specifically comprises the following steps: standing for 6-24 h at 15-50 ℃.
In some embodiments, the molar ratio of the sodium salt to the hexachlorotriphosphazene in the first solution is (3-6): 1.
In some embodiments, the molar ratio of the sodium salt to the potassium salt in the second solution is (1-2): 1, and the molar ratio of the potassium salt to the hexachlorotriphosphazene in the second solution is (3-6): 1.
The preparation method of the inorganic single crystal adopts a first solution containing sodium salt or a second solution containing potassium salt or sodium salt to react with a hexachlorotriphosphazene solution to finally prepare Na3(PO2NH)3·4H2O single crystal or KNa2(PO2NH)3·2H2The O single crystal, the preparation process and the prepared single crystal do not contain heavy metal elements, the preparation process is environment-friendly, and the process is simple.
Based on the same inventive concept, the embodiment of the application also provides a preparation method of the composite film, which comprises the following steps:
s31 and Na prepared by the preparation method3(PO2NH)3·4H2O single crystal or KNa2(PO2NH)3·2H2Adding O single crystal into a second organic solvent to obtain a dispersion liquid;
s32, adding a polymer into the dispersion liquid, and stirring to obtain a polymer dispersion liquid;
and S33, taking the polymer dispersion liquid as spinning liquid, and preparing the composite membrane by using an electrostatic spinning process.
In the examples of the present application, the second organic solvent can dissolve Na3(PO2NH)3·4H2O single crystal or KNa2(PO2NH)3·2H2The O single crystal may be the same as or different from the first organic solvent, and specific examples of the second organic solvent include DMF, NMP, DMSO, dioxane, and the like.
In some embodiments, a polymer is added to the dispersion and stirred at 50-70 ℃ for 10-15 hours to obtain a polymer dispersion, wherein the polymer comprises but is not limited to one of PVDF, a copolymer of PVDF, water-soluble cellulose, polylactic acid and polyimide.
In some embodiments, the polymer dispersion is used as a spinning solution, and the composite film prepared by using an electrostatic spinning process is specifically: and transferring the polymer dispersion liquid to a needle head of an electrostatic spinning device, spinning for 1-3 h at the electric field intensity of 0.5-1.5 MV/m and the receiving roller speed of 2500-3000 rpm to obtain a wet film, and drying the wet film to obtain the composite film.
In some embodiments, Na is present in the polymer dispersion3(PO2NH)3·4H2O single crystal or KNa2(PO2NH)3·2H2The mass ratio of the O single crystal to the polymer is 1 (2-10).
In the method for producing a composite film of the present invention, Na having excellent crystallinity and being monoclinic is selected3(PO2NH)3·4H2The O single crystal is used as a piezoelectric filler, the unit cell of the O single crystal contains a large amount of polar groups, such as Na-O, P-O, N-H and the like, which means that a large amount of dipoles are arranged in the crystal, namely the crystal has piezoelectric activity, and meanwhile, a composite film obtained by compounding the O single crystal with a polymer has excellent flexibility and can be prepared into a simple energy collecting device to be applied to various complex environments; further, by optimizing the synthesis process, the proper Na is selected3(PO2NH)3·4H2The proportion of O and polymer, the piezoelectric device made of the composite film has better piezoelectric output performance, and the device can be used as an energy collecting device, and the collected electric energy can be directly stored in a capacitor, so that the piezoelectric device has excellent application prospect in the fields of energy collection, electric energy storage, use and the like.
The present invention provides a method for producing a composite film, which selects triclinic KNa having excellent crystallinity2(PO2NH)3·2H2The O single crystal is used as a piezoelectric filler, the diameter of the O single crystal is 100-200 um, the length of the O single crystal is 0.5-1 cm, a unit cell of the O single crystal contains a large number of polar groups, such as Na-O, K-O, P-O, N-H and the like, the electro-spinning composite film obtained by compounding the O single crystal with a polymer has excellent flexibility, the content of beta crystal form with piezoelectric activity in the composite film is greatly increased after the O single crystal is oriented by an electric field, and the piezoelectric performance output is favorably improved; furthermore, by optimizing the synthesis process and selecting a proper raw material proportion, the piezoelectric device made of the composite film has better piezoelectric output performance compared with a pure polymer piezoelectric device, meanwhile, the device can also be used as an energy collecting device to effectively collect human body movement energy, and the electric energy collected by the device can be directly stored in a capacitor, so that the device has excellent application prospects in the fields of energy collection, electric energy storage and use and the like.
The following further describes a method for producing an inorganic single crystal, a method for producing a composite film, and applications thereof, with specific examples.
Example 1
The embodiment of the application provides Na3(PO2NH)3·4H2A method for producing an O single crystal, comprising the steps of:
s11, dissolving 0.24g of NaOH in 10mL of water to obtain a first solution;
s12, adding 0.3467g of hexachlorotriphosphazene into 10mL of DMF, and dissolving to obtain a DMF solution;
s13, adding the first solution into DMF solution, stirring uniformly, then placing in a 40 ℃ oven for standing for 24h to obtain 0.2238g of Na3(PO2NH)3·4H2And (4) O crystal product.
The embodiment of the application also provides a preparation method of the composite film, which comprises the following steps:
s31, collecting 100mg of Na prepared above3(PO2NH)3·4H2Adding O single crystal into 10mL of DMF, and performing ultrasonic dispersion to obtain a DMF dispersion liquid;
s32, adding 1g of PVDF into the DMF dispersion liquid, heating to 60 ℃, and stirring for 12 hours to obtain a PVDF dispersion liquid;
s33, transferring the PVDF dispersion liquid to a needle of an electrostatic spinning device, spinning for 2 hours at the electric field intensity of 1MV/m and the receiving roller speed of 2700rpm to obtain a wet film, and drying the wet film at 80 ℃ for 6 hours to obtain the PNONa-PVDF composite film.
Example 2
The embodiment of the application provides a KNa2(PO2NH)3·2H2A method for producing an O single crystal, comprising the steps of:
s21, dissolving 0.3366g of KOH and 0.3506g of NaCl in 10mL of water to obtain a second solution;
s22, adding 0.3467g of hexachlorotriphosphazene into 10mL of DMF, and dissolving to obtain a DMF solution;
s23, adding the second solution into the DMF solution, stirring uniformly, then placing in a 40 ℃ oven for standing for 24 hours to obtain 0.2370g of KNa2(PO2NH)3·2H2And (4) O crystal product.
The embodiment of the application also provides a preparation method of the composite film, which comprises the following steps:
s31, collecting 25mg of KNa prepared by the above method2(PO2NH)3·2H2Adding O single crystal into 10mL of DMF, and performing ultrasonic dispersion to obtain a DMF dispersion liquid;
s32, adding 1g of PVDF into the DMF dispersion liquid, heating to 60 ℃, and stirring for 12 hours to obtain a PVDF dispersion liquid;
s33, transferring the PVDF dispersion liquid to a needle of an electrostatic spinning device, spinning for 2 hours at the electric field intensity of 1MV/m and the receiving roller speed of 2700rpm to obtain a wet film, and drying the wet film at 80 ℃ for 6 hours to obtain the PNONaK-PVDF composite film.
Example 3
The embodiment of the application provides Na3(PO2NH)3·4H2A method for producing an O single crystal, comprising the steps of:
s11, dissolving 0.24g of NaOH in 10mL of water to obtain a first solution;
s12, adding 0.3467g of hexachlorotriphosphazene into 10mL of NMP, and dissolving to obtain an NMP solution;
s13, adding the first solution into the NMP solution, stirring uniformly, then placing the mixture into a 40 ℃ oven, standing for 24 hours, and finally obtaining Na3(PO2NH)3·4H2And (4) O single crystal.
Example 4
The embodiment of the application provides Na3(PO2NH)3·4H2A method for producing an O single crystal, comprising the steps of:
s11, dissolving 0.24g of NaOH in 10mL of water to obtain a first solution;
s12, adding 0.3467g of hexachlorotriphosphazene into 10mL of DMSO, and dissolving to obtain a DMSO solution;
s13, adding the first solution into the DMSO solution, stirring uniformly, then placing in a 40 ℃ oven for standing for 24h to obtain Na3(PO2NH)3·4H2And (4) O single crystal.
Example 5
The embodiment of the application provides Na3(PO2NH)3·4H2A method for producing an O single crystal, comprising the steps of:
s11, dissolving 0.24g of NaOH in 10mL of water to obtain a first solution;
s12, adding 0.3467g of hexachlorotriphosphazene into 10mL of dioxane, and dissolving to obtain dioxane solution;
s13, adding the first solution into dioxane solution, stirring uniformly, then placing in a 40 ℃ oven for standing for 24h to finally obtain Na3(PO2NH)3·4H2And (4) O single crystal.
Example 6
The embodiment of the application provides Na3(PO2NH)3·4H2A method for producing an O single crystal, comprising the steps of:
s11, dissolving 0.3366g of KOH in 10mL of water to obtain a first solution;
s12, adding 0.3467g of hexachlorotriphosphazene into 10mL of NMP, and dissolving to obtain an NMP solution;
s13, adding the first solution into the NMP solution, stirring uniformly, then placing the mixture into a 40 ℃ oven, standing for 24 hours, and finally obtaining Na3(PO2NH)3·4H2And (4) O single crystal.
Example 7
The embodiment of the application provides Na3(PO2NH)3·4H2A method for producing an O single crystal, comprising the steps of:
s11, mixing 0.6360g of Na2CO3Dissolving in 10mL of water to obtain a first solution;
s12, adding 0.3467g of hexachlorotriphosphazene into 10mL of DMF, and dissolving to obtain a DMF solution;
s13, adding the first solution into a DMF solution, stirring uniformly, then placing in a 40 ℃ oven for standing for 24h to finally obtain Na3(PO2NH)3·4H2And (4) O single crystal.
Example 8
The embodiment of the application provides Na3(PO2NH)3·4H2A method for producing an O single crystal, comprising the steps of:
s11, 0.5040g of NaHCO3Dissolving in 10mL of water to obtain a first solution;
s12, adding 0.3467g of hexachlorotriphosphazene into 10mL of DMF, and dissolving to obtain a DMF solution;
s13, adding the first solution into a DMF solution, stirring uniformly, then placing in a 40 ℃ oven for standing for 24h to finally obtain Na3(PO2NH)3·4H2And (4) O single crystal.
Example 9
The embodiment of the application provides Na3(PO2NH)3·4H2A method for producing an O single crystal, comprising the steps of:
s11, adding 0.4922g of CH3COONa is dissolved in 10mL of water to obtain a first solution;
s12, adding 0.3467g of hexachlorotriphosphazene into 10mL of DMF, and dissolving to obtain a DMF solution;
s13, adding the first solution into a DMF solution, stirring uniformly, then placing in a 40 ℃ oven for standing for 24h to finally obtain Na3(PO2NH)3·4H2And (4) O single crystal.
Example 10
The embodiment of the application provides a KNa2(PO2NH)3·2H2A method for producing an O single crystal, comprising the steps of:
s21, dissolving 0.24g of NaOH and 0.4473g of KCl in 10mL of water to obtain a second solution;
s22, adding 0.3467g of hexachlorotriphosphazene into 10mL of DMF, and dissolving to obtain a DMF solution;
s23, adding the second solution into the DMF solution, stirring uniformly, then placing in a 40 ℃ oven for standing for 24h to obtain KNa2(PO2NH)3·2H2And (4) O single crystal.
Example 11
The embodiment of the application provides a KNa2(PO2NH)3·2H2A method for producing an O single crystal, comprising the steps of:
s21, mixing 0.24g NaOH and 0.6005g KHCO3Dissolving in 10mL of water to obtain a second solution;
s22, adding 0.3467g of hexachlorotriphosphazene into 10mL of DMF, and dissolving to obtain a DMF solution;
s23, adding the second solution into the DMF solution, stirring uniformly, then placing in a 40 ℃ oven for standing for 24h to obtain KNa2(PO2NH)3·2H2And (4) O single crystal.
Example 12
The embodiment of the application provides a KNa2(PO2NH)3·2H2A method for producing an O single crystal, comprising the steps of:
s21, adding 0.8280g of K2CO3And 0.3510g of NaCl in 10mL of water to obtain a second solution;
s22, adding 0.3467g of hexachlorotriphosphazene into 10mL of DMF, and dissolving to obtain a DMF solution;
s23, adding the second solution into the DMF solution, stirring uniformly, then placing in a 40 ℃ oven for standing for 24h to obtain KNa2(PO2NH)3·2H2And (4) O single crystal.
Example 13
The embodiment of the application provides a KNa2(PO2NH)3·2H2A method for producing an O single crystal, comprising the steps of:
s21, mixing 0.6005g KHCO3And 0.3510g of NaCl in 10mL of water to obtain a second solution;
s22, adding 0.3467g of hexachlorotriphosphazene into 10mL of DMF, and dissolving to obtain a DMF solution;
s23, adding the second solution into the DMF solution, stirring uniformly, then placing in a 40 ℃ oven for standing for 24h to obtain KNa2(PO2NH)3·2H2And (4) O single crystal.
Performance testing
Na prepared in example 13(PO2NH)3·4H2The appearance of O single crystal is shown in FIG. 1. As can be seen from FIG. 1, Na3(PO2NH)3·4H2The O single crystal is needle-shaped crystal visible to the naked eye.
Na prepared in example 13(PO2NH)3·4H2An optical microscope image of the O single crystal is shown in fig. 2 (size 100um in fig. 2). In fig. 2, the left side shows an optical image in transmitted light, and the right side shows an optical image in polarization mode. The observation of an optical microscope shows that the macroscopic morphology of the crystal is regular, the crystal has obvious polarization property, and the crystallinity is excellent.
Na prepared in example 1 was measured by using a single crystal diffractometer3(PO2NH)3·4H2The single crystal structure of O single crystal is analyzed and found that the molecular formula is H11N3Na3O10P3Namely, hexachlorotriphosphazene is hydrolyzed under alkaline conditions, and the hydrolysis product is coordinated with Na ions; na (Na)3(PO2NH)3·4H2The O single crystal is monoclinic, P21/nSpace group, cell parameter of α＝90°，β＝96.907(2)°，γ＝90°。
The surface morphology of the PNONa-PVDF composite membrane prepared in example 1 was tested, and the result is shown in fig. 3. It can be seen from fig. 3 that the fibers of the PNONa-PVDF composite film are highly oriented, and there is no significant entanglement and balling between the fibers.
The PNONa-PVDF composite film prepared in example 1 was cut into a square of 2 × 2cm, copper electrodes were attached to both sides, and the lead was led out and then encapsulated with polyimide to prepare a piezoelectric nano-generator PNONa-PVDF device.
The open circuit voltage of the PNONa-PVDF device was measured by an electrometer under the conditions of a maximum stress of 40N and a stress frequency of 1Hz, and the result is shown in FIG. 4. It can be seen from figure 4 that the open circuit voltage output of the PNONa-PVDF device is 10.5V.
The PNONa-PVDF device was further tested to find the piezoelectric output performance under different applied loads under the conditions of the maximum stress of 40N and the stress frequency of 1Hz, and the result is shown in fig. 5. As can be seen from FIG. 5, when the external load is 10 Ω, the output power density of the device reaches the maximum value, which is 0.5 μ W cm-2。
The mechanical energy collected by the PNONa-PVDF device may be converted into electric energy, and then the electric energy may be rectified and stored in the capacitor through the full bridge rectifier, and the electric quantity stored in the capacitor may light the LED, as shown in fig. 6.
KNa obtained in example 22(PO2NH)3·2H2The appearance of O single crystal is shown in FIG. 7. KNa can be seen from FIG. 72(PO2NH)3·2H2The O single crystal is needle-shaped crystal visible to the naked eye.
KNa obtained in example 22(PO2NH)3·2H2An optical microscope photograph of the O single crystal is shown in FIG. 8 (size 100um in FIG. 11). In fig. 8, the left side shows an optical picture in transmitted light, and the right side shows an optical picture in polarization mode. The observation by an optical microscope shows that the crystal is flat cuboid, has the diameter of micrometer level, has obvious polarization property and shows excellent crystallinity.
KNa obtained by subjecting example 2 to a single crystal diffractometer2(PO2NH)3·2H2The single crystal structure of O single crystal is analyzed and found that the molecular formula is H7K0.97N3Na2O8P3Namely, hexachlorotriphosphazene is hydrolyzed under alkaline conditions, and the hydrolysis product is coordinated with Na and K ions; KNa2(PO2NH)3·2H2The O single crystal is a triclinic system, P-1 space group, and the unit cell parameter is α＝75.882(2)°，β＝83.694(2)°，γ＝77.365(2)°。
The surface morphology of the PNONaK-PVDF composite film prepared in example 2 was tested, and the result is shown in fig. 9. It can be seen from fig. 9 that the PNONaK-PVDF composite film has highly oriented fibers, and there is no significant entanglement and balling between the fibers.
The PNONaK-PVDF composite film prepared in example 2 was cut into a square of 2 × 2cm, copper electrodes were attached to both sides, and the lead was led out and then encapsulated with polyimide to prepare a piezoelectric nano-generator PNONaK-PVDF device.
The open circuit voltage of the PNONaK-PVDF device was measured by an electrometer under the conditions of a maximum stress of 40N and a stress frequency of 1Hz, and the result is shown in FIG. 10. It can be seen from figure 10 that the PNONaK-PVDF device open circuit voltage output is 4.5V.
The PNONaK-PVDF device was further tested to find the piezoelectric output performance under different applied loads under the conditions of the maximum stress of 40N and the stress frequency of 1Hz, and the result is shown in fig. 11. As can be seen from FIG. 11, when the external load is 20 Ω, the output power density of the PNONaK-PVDF device reaches the maximum value, which is 0.35 μ W cm-2。
The stability test of the PNONaK-PVDF device was carried out under the conditions of 40N force application and 3Hz force application frequency, and the result is shown in FIG. 12. As can be seen from fig. 12, the output voltage of the device was found to be stable after being stressed 1000 times, indicating that the PNONaK-PVDF device has excellent durability and long service life.
In order to test the practicability of the PNONAK-PVDF device, the exercise process of walking and running of an adult with the weight of 65kg is used for testing the collection effect of the device on the human body exercise energy, and the results are shown in FIGS. 15-16. Specifically, the PNONAK-PVDF device is attached to a sole of a shoe, and when the shoe is worn, force is applied to the device when the shoe walks or runs, so that mechanical energy generated by human body movement is collected and converted into electric energy.
As can be seen from fig. 13, a capacitor having a capacity of 2uF can be charged to about 3V after 50 seconds in the walking state of the human body; as can be seen from fig. 14, the human body can be charged to about 6V after 50 seconds in the running state, which shows that the PNONaK-PVDF device can effectively collect and convert the motion energy of the human body in the real environment, and exhibits excellent electromechanical coupling performance.
Na prepared in examples 3 to 63(PO2NH)3·4H2The appearance of O single crystal is shown in FIG. 15. In FIG. 15, A corresponds to Na prepared in example 33(PO2NH)3·4H2O Single Crystal and B correspond to Na prepared in example 43(PO2NH)3·4H2O Single Crystal and C correspond to Na prepared in example 53(PO2NH)3·4H2O Single Crystal and D correspond to Na prepared in example 63(PO2NH)3·4H2And (4) O single crystal.
Na prepared in examples 7 to 93(PO2NH)3·4H2The appearance of the O single crystal is shown in FIG. 16. In FIG. 15, A corresponds to Na prepared in example 73(PO2NH)3·4H2O Single Crystal and B correspond to Na prepared in example 83(PO2NH)3·4H2O Single Crystal and C correspond to Na prepared in example 93(PO2NH)3·4H2And (4) O single crystal.
KNa obtained in examples 10 to 132(PO2NH)3·2H2The appearance of O single crystal is shown in FIG. 17. In FIG. 17, A corresponds to KNa obtained in example 102(PO2NH)3·2H2O Single Crystal, B KNa prepared in example 112(PO2NH)3·2H2O Single Crystal and C correspond to KNa obtained in example 122(PO2NH)3·2H2O single crystal, D pairKNa prepared in example 132(PO2NH)3·2H2And (4) O single crystal.
As can be seen from the above FIGS. 15 to 17, Na can be prepared by using different sodium salts, potassium salts and solvents3(PO2NH)3·4H2O single crystal or KNa2(PO2NH)3·2H2And (4) O single crystal.
In conclusion, the invention adopts a brand-new, simple and efficient synthesis method to prepare two inorganic Na with high crystallinity3(PO2NH)3·4H2O single crystal and KNa2(PO2NH)3·2H2Because of the highly asymmetric crystal structure and polar groups of the O single crystal, the O single crystal is compounded with PVDF respectively to prepare a PNONa-PVDF composite membrane and a PNONaK-PVDF composite membrane which have piezoelectric activity and flexibility, and the two composite membranes have higher piezoelectric output performance compared with a pure PVDF membrane.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
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