Diaphragm with piezoelectric ceramic coating and manufacturing method thereof

Abstract

The embodiment of the invention provides a diaphragm coated with piezoelectric ceramics and a manufacturing method thereof, and the method comprises the following steps: stretching a polymer film, immersing the polymer film in liquid ammonia, and cooling to obtain a modified polymer film; the preparation method comprises the following steps: mixing piezoelectric ceramic powder and an adhesive, pre-pressing to obtain a pre-pressed block, grinding, sieving, injecting into a mold, carrying out dry pressing to obtain a blank, sintering the blank at high temperature to obtain a piezoelectric ceramic body, grinding, sieving, and mixing with a viscous solvent to form piezoelectric ceramic powder suspension; and uniformly coating the suspension on the surface of the modified polymer film, heating, and polarizing the obtained diaphragm in a polarization electric field to obtain the piezoelectric ceramic coated diaphragm. The diaphragm coated with the piezoelectric ceramic is manufactured by adopting the method, the piezoelectric ceramic particles on the diaphragm are driven to vibrate by introducing direct-current pulse current, and metal ion crystals on the diaphragm are broken through mechanical force, so that crystal nuclei can be effectively prevented from being generated on the inner side of a battery pole piece.

Description

Technical Field

[0001] The present invention relates to the technical field of thin film material manufacturing, and particularly to a diaphragm with piezoelectric ceramic coating and a manufacturing method thereof. Background Art

[0002] With the rapid development of new energy technologies, rechargeable batteries are widely used in various electrical appliances. In the prior art methods, in order to increase the strength and ion migration efficiency of the diaphragm on the inner side of the battery electrode plate, alumina (Al2O3) is usually doped in the diaphragm or alumina particles are laid on the surface of the diaphragm. However, in the actual application process, for rechargeable batteries using traditional diaphragms, after repeated charge and discharge, dendrites will grow due to the deposition of metal ions caused by the change of the electrochemical properties of the metal ions on the electrode plate. After the dendrites are generated, the Coulomb efficiency of the battery will be seriously reduced, and the diaphragm arranged on the inner side of the electrode plate will be damaged, that is, the charging efficiency and effective charging capacity of the rechargeable battery are affected; at the same time, after the dendrites are generated, the charging heat generation will be significantly increased, thus seriously affecting the charging safety of the battery. Therefore, the diaphragm used in the prior art methods for rechargeable batteries has the problem of easy deposition of metal ions and generation of dendrites. Summary of the Invention

[0003] Embodiments of the present invention provide a diaphragm with piezoelectric ceramic coating and a manufacturing method thereof, aiming to solve the problem that the diaphragm used in the prior art methods for rechargeable batteries is prone to deposit metal ions and generate dendrites.

[0004] Embodiments of the present invention provide a manufacturing method of a diaphragm with piezoelectric ceramic coating, and the method includes:

[0005] Longitudinally stretching a polymer film at 165 - 235 °C, and the longitudinal stretching ratio is 4 - 9; then transversely stretching at 135 - 185 °C, and the stretching ratio is 2.5 - 5;

[0006] Immersing the stretched polymer film in liquid ammonia for 2 - 5 minutes to cool the polymer film to obtain a modified polymer film;

[0007] Mixing piezoelectric ceramic powder and an adhesive according to a mass ratio of (92 - 96):(2 - 5), stirring evenly, and performing pre-pressing treatment under a pressure of 6 - 15 MPa to obtain a pre-pressed block. Grinding the pre-pressed block and sieving it, then injecting it into a mold and dry-pressing it under a pressure of 8 - 22 MPa to obtain a blank;

[0008] Placing the blank in a sintering furnace at 900 - 1200 °C for sintering for 2 - 5 hours to obtain a piezoelectric ceramic body;

[0009] Grinding the piezoelectric ceramic body and sieving it, and mixing the sieved piezoelectric ceramic powder with a viscous solvent to form a piezoelectric ceramic powder suspension;

[0010] The piezoelectric ceramic powder suspension is uniformly coated on the surface of the modified polymer film, and the modified polymer film is placed in an oven and the heating temperature is set to 95-110 °C to volatilize the viscous solvent, obtaining an initial diaphragm;

[0011] The initial diaphragm is polarized under an environment of 140-180 °C and a polarization electric field with a fixed field strength direction to obtain a diaphragm with a piezoelectric ceramic coating.

[0012] The manufacturing method of the diaphragm with a piezoelectric ceramic coating, wherein the manufacturing method of the polymer film includes:

[0013] Polytetrafluoroethylene powder, petroleum ether, and a silane coupling agent are mixed evenly in a reaction kettle according to a mass ratio of 10:2.2:(0.2-0.5), and sealed and cured at 40-50 °C for 6-8 hours to obtain a paste;

[0014] The above paste is flattened and extended under a pressure of 5-9.5 MPa by a pressure bar to form a polymer sheet; the temperature for flattening and extending is 62-75 °C;

[0015] The polymer sheet is placed in an oven and the heating temperature is set to 120-130 °C to dry and remove petroleum ether;

[0016] It is further sent into a radiation box for radiation cross-linking treatment to obtain a cross-linked polytetrafluoroethylene film;

[0017] A solution obtained by dissolving poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] in chlorobenzene at a concentration of 6-25 mg / mL is uniformly coated on the cross-linked polytetrafluoroethylene film and annealed to obtain a polymer film.

[0018] The manufacturing method of the diaphragm with a piezoelectric ceramic coating, wherein the piezoelectric ceramic powder material is obtained by mixing Pb3O4 powder, GeO2 powder, NiO powder, BaCO3 powder, ZrO2 powder, SnO2 powder, and TiO2 powder according to a mass ratio of (7.5-9.5):(0.2-0.5):(0.3-0.8):(0.6-1.8):(4.6-5):(3.2-3.8):(0.6-1.3).

[0019] The manufacturing method of the diaphragm with a piezoelectric ceramic coating, wherein the viscous solvent is one or a combination of isopropanol, cyclohexane, and methylcyclohexanol.

[0020] The manufacturing method of the diaphragm with a piezoelectric ceramic coating, wherein the step of grinding the piezoelectric ceramic body and then sieving includes: sieving the ground piezoelectric ceramic powder through 1200-4000 meshes.

[0021] The manufacturing method of the diaphragm with piezoelectric ceramic coating, wherein the mass ratio of the piezoelectric ceramic powder in the piezoelectric ceramic powder suspension is 0.8 - 2%.

[0022] The manufacturing method of the diaphragm with piezoelectric ceramic coating, wherein the coating amount of the piezoelectric ceramic powder suspension on the surface of the modified polymer film is 45 - 200 ml / m 2 。

[0023] The manufacturing method of the diaphragm with piezoelectric ceramic coating, wherein the electric field strength of the polarization electric field is 160 - 350 V / m.

[0024] The manufacturing method of the diaphragm with piezoelectric ceramic coating, wherein the polarization duration is 20 - 45 minutes.

[0025] The embodiment of the present invention also provides a diaphragm with piezoelectric ceramic coating. The diaphragm is prepared by the above manufacturing method of the diaphragm with piezoelectric ceramic coating. The diaphragm includes a polymer film and piezoelectric ceramic particles laid on the surface layer of the polymer film;

[0026] The polymer film is formed by laminating a cross-linked polytetrafluoroethylene film and a poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] film; The piezoelectric ceramic particles are laid on both sides of the polymer film;

[0027] The polymer film is uniformly distributed with film through-holes. The thickness of the polymer film is 20 - 140 μm, and the aperture of the film through-holes is 20 - 50 μm;

[0028] The piezoelectric ceramic particles are lead zirconate titanate ceramic particles, and the particle size of the piezoelectric ceramic particles is 0.5 - 25 μm.

[0029] An embodiment of the present invention provides a diaphragm with piezoelectric ceramic coating and a manufacturing method thereof. The method involves stretching a polymer film and then immersing it in liquid ammonia for cooling to obtain a modified polymer film. Piezoelectric ceramic powder is mixed with an adhesive and pre-pressed to obtain a pre-pressed block, which is ground, sieved, injected into a mold, and dry-pressed to form a blank. The blank is sintered at high temperature to obtain a piezoelectric ceramic body, which is ground, sieved, and mixed with a viscous solvent to form a piezoelectric ceramic powder suspension. The suspension is evenly coated on the surface of the modified polymer film and heated. The resulting diaphragm is polarized under an environment of 140 - 180 °C and a polarization electric field with a fixed field strength direction to obtain a diaphragm with piezoelectric ceramic coating. By using the above method, the polymer film is stretched and cooled for modification to form film through-holes on the polymer film, and then piezoelectric ceramic particles are laid on the surface of the polymer film to obtain a diaphragm with piezoelectric ceramic coating. A direct current pulse current is passed through to drive the piezoelectric ceramic particles on the diaphragm to generate vibrations, and the diaphragm generates mechanical expansion and contraction to break the metal ion crystals on the diaphragm through mechanical force, thereby effectively preventing the generation of crystal nuclei on the inner side of the battery electrode sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0031] Figure 1 It is a flowchart of the manufacturing method of the diaphragm with piezoelectric ceramic coating provided by the embodiment of the present invention;

[0032] Figure 2 It is a schematic cross-sectional structure diagram of the diaphragm with piezoelectric ceramic coating provided by the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the protection scope of the present invention.

[0034] It should be understood that when used in this specification and the appended claims, the terms "comprises" and "comprising" indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0035] It should also be understood that the terms used in the specification of the present invention herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0036] It should be further understood that the term "and / or" used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0037] Please refer to Figure 1 , Figure 1 FIG. is a flowchart of a method for manufacturing a diaphragm with a piezoelectric ceramic coating provided by an embodiment of the present invention. The method for manufacturing the diaphragm is used to manufacture the diaphragm with a piezoelectric ceramic coating in the embodiments of the present application. As shown in the figure, the method for manufacturing the diaphragm with a piezoelectric ceramic coating includes steps S110-S170.

[0038] S110. Longitudinally stretch the polymer film at 165-235 °C, and the longitudinal stretch ratio is 4-9; then transversely stretch it at 135-185 °C, and the stretch ratio is 2.5-5.

[0039] The polymer film can be longitudinally stretched at 165-235 °C, and the longitudinal stretch ratio is 4-9, preferably 6-7; then the film is transversely stretched at 135-185 °C, and the stretch ratio is 2.5-5, preferably 3.5-4.5. Specifically, the polymer film can be polytetrafluoroethylene. Through the above stretching, tiny film through-holes can be formed on the polymer film, and the fibers in the polymer film are stretched, and the voids between the fibers are formed as film through-holes.

[0040] Specifically, the preparation method of the polymer film includes the following steps: mixing polytetrafluoroethylene powder, petroleum ether and a silane coupling agent in a mass ratio of 10:2.2:(0.2-0.5) evenly in a reaction kettle, sealing and curing at 40-50 °C for 6-8 hours to obtain a paste; flattening and extending the above paste under a pressure of 5-9.5 MPa through a pressure bar to form a polymer sheet; the temperature of flattening and extending is 62-75 °C; placing the polymer sheet in an oven and setting the heating temperature to 120-130 °C to dry and remove petroleum ether; further feeding it into a radiation box for radiation cross-linking treatment to obtain a cross-linked polytetrafluoroethylene film; uniformly coating a solution obtained by dissolving poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] in chlorobenzene at a concentration of 6-25 mg / mL on the cross-linked polytetrafluoroethylene film and annealing it to obtain a polymer film.

[0041] Polytetrafluoroethylene powder, petroleum ether and KH-550 silane coupling agent (γ-aminopropyltriethoxysilane) can be mixed according to a preset mass ratio and heated and cured to prepare a paste. The paste is flattened and extended under a pressure of 5-9.5 MPa through a multi-stage pressing rod to form a polymer thin film. The pressing pressure and pressing temperature of the multi-stage pressing rod gradually increase. For example, the pressing pressure of the first-stage pressing rod is 5.5 MPa and the pressing temperature is 62 °C; the pressing pressure of the second-stage pressing rod is 5.8 MPa and the pressing temperature is 64 °C; the pressing pressure of the third-stage pressing rod is 6.2 MPa and the pressing temperature is 66 °C... Then, the polymer thin film is heated to remove petroleum ether, and then sent into a radiation box for radiation cross-linking treatment. The radiation dose is controlled at 6-30 kGy to obtain a cross-linked polytetrafluoroethylene film. Then, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] dissolved in chlorobenzene is uniformly coated on the cross-linked polytetrafluoroethylene film and annealed at 105-125 °C for 7-10 minutes to obtain a polymer thin film.

[0042] S120. Immerse the stretched polymer thin film in liquid ammonia for 2-5 minutes to cool the polymer thin film to obtain a modified polymer thin film.

[0043] Furthermore, place the stretched polymer thin film in liquid ammonia for 2-5 minutes to cool and modify the polymer thin film, and make the film through-holes in the polymer thin film shrink and be shaped, avoiding the re-closure of the film through-holes due to film retraction. After immersion in liquid ammonia, a modified polymer thin film can be obtained.

[0044] S130. Mix piezoelectric ceramic powder and binder according to a mass ratio of (92-96):(2-5) and stir evenly, and perform pre-pressing treatment under a pressure of 6-15 MPa to obtain a pre-pressed block. Grind the pre-pressed block and sieve it, then inject it into a mold and dry-press it into shape under a pressure of 8-22 MPa to obtain a green body.

[0045] Mix piezoelectric ceramic powder and binder according to a certain mass ratio and stir evenly. Among them, the piezoelectric ceramic powder can be PZT powder. For example, the piezoelectric ceramic powder can be selected as being obtained by mixing Pb3O4 powder, GeO2 powder, NiO powder, BaCO3 powder, ZrO2 powder, SnO2 powder and TiO2 powder according to a mass ratio of (7.5-9.5):(0.2-0.5):(0.3-0.8):(0.6-1.8):(4.6-5):(3.2-3.8):(0.6-1.3). The binder is obtained by mixing glycerol, alcohol and distilled water according to a mass ratio of 16:4:80. First, perform pre-pressing treatment with a lower pressure, and then perform dry-pressing forming with a higher pressure to obtain a green body.

[0046] S140. Sinter the green body at 900-1200 °C for 2-5 hours to obtain a piezoelectric ceramic body.

[0047] The green body is subjected to high-temperature sintering to obtain a piezoelectric ceramic body. Among them, the green body can be first heated from room temperature to 900 - 1000 °C and maintained for 0.5 hours, and then heated from the current temperature to 1001 - 1200 °C and maintained for 1.5 - 4.5 hours to complete the sintering operation.

[0048] S150. The piezoelectric ceramic body is ground and then sieved. The piezoelectric ceramic powder obtained by sieving is mixed with a viscous solvent to form a piezoelectric ceramic powder suspension.

[0049] The piezoelectric ceramic body is ground, and the ground ceramic particles are sieved. Among them, the piezoelectric ceramic powder obtained by grinding can be sieved with 1200 - 4000 meshes. The piezoelectric ceramic powder obtained after sieving is mixed with a viscous solvent to obtain a piezoelectric ceramic powder suspension; among them, the viscous solvent is one or a combination of isopropyl alcohol, cyclohexane, and methyl cyclohexanol. The mass ratio of the piezoelectric ceramic powder in the piezoelectric ceramic powder suspension is 0.8 - 2%.

[0050] S160. The piezoelectric ceramic powder suspension is evenly coated on the surface of the modified polymer film, and the modified polymer film is placed in an oven and the heating temperature is set to 95 - 110 °C to volatilize the viscous solvent, obtaining an initial diaphragm.

[0051] The piezoelectric ceramic powder suspension is evenly coated on both surfaces of the modified polymer film, and then the modified polymer film is placed in an oven and the heating temperature is set to 95 - 110 °C to volatilize the viscous solvent; specifically, the piezoelectric ceramic powder suspension can be evenly coated on both surfaces of the modified polymer film simultaneously and then heated; or the piezoelectric ceramic powder suspension can be evenly coated on one surface of the modified polymer film for heating treatment, and then the piezoelectric ceramic powder suspension is evenly coated on the other surface of the modified polymer film for heating treatment. After heating to volatilize the viscous solvent, an initial diaphragm can be obtained. Among them, the coating amount of the piezoelectric ceramic powder suspension on the surface of the modified polymer film is 45 - 200 ml / m 2 。

[0052] S170. The initial diaphragm is polarized in an environment of 140 - 180 °C and a polarization electric field with a fixed field strength direction to obtain a diaphragm with a piezoelectric ceramic coating.

[0053] The initial diaphragm obtained in the above steps is polarized in a thermal environment of 140 - 180 °C and a polarization electric field with a fixed field strength direction. Specifically, the electric field strength of the polarization electric field is 160 - 350 V / m, and the polarization time is 20 - 45 minutes. After polarization is completed, a diaphragm with a piezoelectric ceramic coating can be obtained.

[0054] The diaphragm with piezoelectric ceramic coating prepared by the above method is as follows Figure 2 shown. The diaphragm with piezoelectric ceramic coating includes a polymer film 1 and piezoelectric ceramic particles 2 laid on the surface layer of the polymer film 1; the polymer film 1 is formed by laminating a cross-linked polytetrafluoroethylene film 11 and a poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] film 12; the piezoelectric ceramic particles 2 are laid on both side surfaces of the polymer film 1; film through holes 101 are uniformly distributed on the polymer film 1, the thickness of the polymer film 1 is 20-140 μm, and the aperture of the film through holes 101 is 20-50 μm; the piezoelectric ceramic particles 2 are lead zirconate titanate ceramic particles, and the particle size of the piezoelectric ceramic particles 2 is 0.5-25 μm. Among them, the ratio of the thickness of the cross-linked polytetrafluoroethylene film 11 to the overall thickness of the polymer film 1 is 0.55-0.7.

[0055] The following is an illustration of the specific implementation process and beneficial effects of the solution through comparisons of multiple embodiments.

[0056] Example 1

[0057] The polymer film is longitudinally stretched at 210°C, and the longitudinal stretching ratio is 6.8; then it is transversely stretched at 170°C, and the stretching ratio is 4.

[0058] Specifically, the preparation method of the polymer film includes the following steps: Mix polytetrafluoroethylene powder, petroleum ether, and KH-550 silane coupling agent (γ-aminopropyltriethoxysilane) in a reaction kettle in a mass ratio of 10:1.8:0.3, and seal and cure at 45°C for 6.5 hours to obtain a paste; flatten and extend the above paste through an eight-stage pressure bar to obtain a polymer thin sheet. The pressing pressure of the first-stage pressure bar is 5.5 MPa, and the pressing temperature is 62°C; the pressing pressure of the second-stage pressure bar is 5.8 MPa, and the pressing temperature is 64°C; the pressing pressure of the third-stage pressure bar is 6.2 MPa, and the pressing temperature is 66°C; the pressing pressure of the fourth-stage pressure bar is 6.8 MPa, and the pressing temperature is 68°C; the pressing pressure of the fifth-stage pressure bar is 7.4 MPa, and the pressing temperature is 70°C; the pressing pressure of the sixth-stage pressure bar is 8 MPa, and the pressing temperature is 72°C; the pressing pressure of the seventh-stage pressure bar is 8.8 MPa, and the pressing temperature is 74°C; the pressing pressure of the eighth-stage pressure bar is 9.5 MPa, and the pressing temperature is 75°C. Place the polymer thin sheet in an oven and set the heating temperature to 125°C to dry and remove petroleum ether; further send it into a radiation box for radiation cross-linking treatment with a radiation intensity of 12 kGy to obtain a cross-linked polytetrafluoroethylene film; uniformly coat the solution obtained by dissolving poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] in chlorobenzene at a concentration of 15 mg / mL on the cross-linked polytetrafluoroethylene film and anneal at 108°C for 8 minutes to obtain a polymer film.

[0059] Further, place the stretched polymer film in liquid ammonia for 4 minutes to cool and modify the polymer film.

[0060] Mix lead zirconate titanate powder and binder in a mass ratio of 95:5 and stir evenly, and perform pre-pressing treatment under a pressure of 10 MPa to obtain a pre-pressed block. Grind the pre-pressed block and sieve it, then inject it into a mold and dry-press it into shape under a pressure of 18 MPa to obtain a green body. Among them, the lead zirconate titanate powder is obtained by mixing Pb3O4 powder, GeO2 powder, NiO powder, BaCO3 powder, ZrO2 powder, SnO2 powder, and TiO2 powder in a mass ratio of 8:0.3:0.5:1.5:5:3.6:1.1, and the binder is obtained by mixing glycerol, alcohol, and distilled water in a mass ratio of 16:4:80.

[0061] Perform high-temperature sintering on the green body to obtain a piezoelectric ceramic body. Specifically, first heat the green body from room temperature to 960°C and hold for 0.5 hour, then heat the green body from the current temperature to 1120°C and hold for 3.5 hours to complete the sintering operation.

[0062] The piezoelectric ceramic body is ground, and the ground piezoelectric ceramic powder is sieved through a 2500-mesh sieve. The sieved piezoelectric ceramic powder is mixed with a viscous solvent to obtain a piezoelectric ceramic powder suspension; wherein, the viscous solvent is cyclohexane. The mass ratio of the piezoelectric ceramic powder in the piezoelectric ceramic powder suspension is 1.5%.

[0063] The piezoelectric ceramic powder suspension is evenly coated on both surfaces of the modified polymer film, and then the modified polymer film is placed in an oven and the heating temperature is set at 98 °C to volatilize the viscous solvent; wherein, the coating amount of the piezoelectric ceramic powder suspension on the surface of the modified polymer film is 120 ml / m 2 。

[0064] The initial diaphragm obtained in the above steps is polarized under a thermal environment of 165 °C and a polarization electric field with a fixed field strength direction. Specifically, the electric field strength of the polarization electric field is 220 V / m, wherein the polarization duration is 30 minutes. After polarization is completed, a diaphragm with a piezoelectric ceramic coating can be obtained.

[0065] Example 2

[0066] The polymer film is longitudinally stretched at 210 °C with a longitudinal stretching ratio of 6.8; then it is transversely stretched at 170 °C with a stretching ratio of 4.

[0067] Specifically, the preparation method of the polymer film includes the following steps: Mix polytetrafluoroethylene powder, petroleum ether, and KH-550 silane coupling agent (γ-aminopropyltriethoxysilane) in a reaction kettle in a mass ratio of 10:1.8:0.3, and seal and cure at 45 °C for 6.5 hours to obtain a paste; The above paste is flattened and extended by an eight-stage pressure rod to obtain a polymer sheet. The pressing pressure of the first-stage pressure rod is 5.5 MPa and the pressing temperature is 62 °C; the pressing pressure of the second-stage pressure rod is 5.8 MPa and the pressing temperature is 64 °C; the pressing pressure of the third-stage pressure rod is 6.2 MPa and the pressing temperature is 66 °C; the pressing pressure of the fourth-stage pressure rod is 6.8 MPa and the pressing temperature is 68 °C; the pressing pressure of the fifth-stage pressure rod is 7.4 MPa and the pressing temperature is 70 °C; the pressing pressure of the sixth-stage pressure rod is 8 MPa and the pressing temperature is 72 °C; the pressing pressure of the seventh-stage pressure rod is 8.8 MPa and the pressing temperature is 74 °C; the pressing pressure of the eighth-stage pressure rod is 9.5 MPa and the pressing temperature is 75 °C. The polymer sheet is placed in an oven and the heating temperature is set at 125 °C to dry and remove petroleum ether; it is further sent to a radiation box for radiation cross-linking treatment with a radiation intensity of 12 kGy to obtain a cross-linked polytetrafluoroethylene film; A solution obtained by dissolving poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] in chlorobenzene at a concentration of 15 mg / mL is evenly coated on the cross-linked polytetrafluoroethylene film and annealed at 108 °C for 8 minutes to obtain a polymer film.

[0068] Further, the stretched polymer film is placed in liquid ammonia for 4 minutes to cool and modify the polymer film.

[0069] Lead zirconate titanate powder and binder are mixed and stirred evenly according to a mass ratio of 95:5, and pre-pressed under a pressure of 10 MPa to obtain a pre-pressed block. After the pre-pressed block is ground and sieved, it is injected into a mold and dry-pressed into a blank under a pressure of 18 MPa. Among them, the lead zirconate titanate powder is obtained by mixing Pb3O4 powder, GeO2 powder, NiO powder, BaCO3 powder, ZrO2 powder, SnO2 powder and TiO2 powder according to a mass ratio of 9:0.2:0.3:1.2:4.8:3.5:1, and the binder is obtained by mixing glycerol, alcohol and distilled water according to a mass ratio of 16:4:80.

[0070] The blank is subjected to high-temperature sintering to obtain a piezoelectric ceramic body. Among them, the blank is first heated from room temperature to 960 °C and maintained for 0.5 hour, and then the blank is heated from the current temperature to 1120 °C and maintained for 3.5 hours to complete the sintering operation.

[0071] The piezoelectric ceramic body is ground, and the ground piezoelectric ceramic powder is sieved through 2500 meshes. The sieved piezoelectric ceramic powder is mixed with a viscous solvent to obtain a piezoelectric ceramic powder suspension; among them, the viscous solvent is cyclohexane. The mass ratio of the piezoelectric ceramic powder in the piezoelectric ceramic powder suspension is 1.5%.

[0072] The piezoelectric ceramic powder suspension is evenly coated on both surfaces of the modified polymer film, and then the modified polymer film is placed in an oven and the heating temperature is set to 98 °C to volatilize the viscous solvent; among them, the coating amount of the piezoelectric ceramic powder suspension on the surface of the modified polymer film is 120 ml / m 2 。

[0073] The initial diaphragm obtained in the above steps is polarized in a thermal environment at 165 °C and a polarization electric field with a fixed field strength direction. Specifically, the electric field strength of the polarization electric field is 220 V / m, and the polarization duration is 30 minutes. After polarization, a diaphragm with a piezoelectric ceramic coating can be obtained.

[0074] Example 3

[0075] The polymer film is longitudinally stretched at 210 °C, and the longitudinal stretching ratio is 6.8; then it is transversely stretched at 170 °C, and the stretching ratio is 4.

[0076] Specifically, the preparation method of the polymer film includes the following steps: Mix polytetrafluoroethylene powder, petroleum ether, and KH-550 silane coupling agent (γ-aminopropyltriethoxysilane) in a reaction kettle in a mass ratio of 10:1.8:0.3, and cure it in a sealed state at 45°C for 6.5 hours to obtain a paste; Flatten and extend the above paste through an eight-stage press bar to obtain a polymer sheet. The pressing pressure of the first-stage press bar is 5.5 MPa and the pressing temperature is 62°C; The pressing pressure of the second-stage press bar is 5.8 MPa and the pressing temperature is 64°C; The pressing pressure of the third-stage press bar is 6.2 MPa and the pressing temperature is 66°C; The pressing pressure of the fourth-stage press bar is 6.8 MPa and the pressing temperature is 68°C; The pressing pressure of the fifth-stage press bar is 7.4 MPa and the pressing temperature is 70°C; The pressing pressure of the sixth-stage press bar is 8 MPa and the pressing temperature is 72°C; The pressing pressure of the seventh-stage press bar is 8.8 MPa and the pressing temperature is 74°C; The pressing pressure of the eighth-stage press bar is 9.5 MPa and the pressing temperature is 75°C. Place the polymer sheet in an oven and set the heating temperature to 125°C to dry and remove petroleum ether; Further send it into a radiation box for radiation cross-linking treatment with a radiation intensity of 12 kGy to obtain a cross-linked polytetrafluoroethylene film; A solution obtained by dissolving poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] in chlorobenzene at a concentration of 15 mg / mL is uniformly coated on the cross-linked polytetrafluoroethylene film and annealed at 108°C for 8 minutes to obtain a polymer film.

[0077] Further, place the stretched polymer film in liquid ammonia for 4 minutes to cool and modify the polymer film.

[0078] Mix lead zirconate titanate powder and binder in a mass ratio of 95:5 and stir evenly, and perform pre-pressing treatment under a pressure of 10 MPa to obtain a pre-pressed block. After grinding the pre-pressed block and sieving it, inject it into a mold and dry-press it into shape under a pressure of 18 MPa to obtain a green body. Among them, the lead zirconate titanate powder is obtained by mixing Pb3O4 powder, GeO2 powder, NiO powder, BaCO3 powder, ZrO2 powder, SnO2 powder, and TiO2 powder in a mass ratio of 8:0.4:0.6:1.2:5:3.6:1, and the binder is obtained by mixing glycerol, alcohol, and distilled water in a mass ratio of 16:4:80.

[0079] Perform high-temperature sintering on the green body to obtain a piezoelectric ceramic body. Specifically, first heat the green body from room temperature to 960°C and hold for 0.5 hours, and then heat the green body from the current temperature to 1120°C and hold for 3.5 hours to complete the sintering operation.

[0080] Grind the piezoelectric ceramic body and sieve the obtained piezoelectric ceramic powder through a 2500-mesh sieve. Mix the sieved piezoelectric ceramic powder with a viscous solvent to obtain a piezoelectric ceramic powder suspension; wherein, the viscous solvent is cyclohexane. The mass ratio of the piezoelectric ceramic powder in the piezoelectric ceramic powder suspension is 1.5%.

[0081] Uniformly coat the two surfaces of the modified polymer film with the piezoelectric ceramic powder suspension, and then place the modified polymer film in an oven and set the heating temperature to 98 °C to volatilize the viscous solvent; wherein, the coating amount of the piezoelectric ceramic powder suspension on the surface of the modified polymer film is 120 ml / m 2 .

[0082] Place the initial diaphragm obtained in the above steps in a thermal environment at 165 °C and a polarization electric field with a fixed field strength direction for polarization. Specifically, the electric field strength of the polarization electric field is 220 V / m, wherein the polarization duration is 30 minutes. After the polarization is completed, a diaphragm with a piezoelectric ceramic coating can be obtained.

[0083] Example 4

[0084] Stretch the polymer film longitudinally at 210 °C with a longitudinal stretch ratio of 6.8; then stretch it transversely at 170 °C with a stretch ratio of 4.

[0085] Specifically, the preparation method of the polymer film includes the following steps: Mix polytetrafluoroethylene powder, petroleum ether, and KH-550 silane coupling agent (γ-aminopropyltriethoxysilane) in a reaction kettle in a mass ratio of 10:1.8:0.3, and seal and cure at 45°C for 6.5 hours to obtain a paste; flatten and extend the above paste through a ten-stage pressing rod to obtain a polymer thin sheet. The pressing pressure of the first-stage pressing rod is 5.5 MPa, and the pressing temperature is 62°C; the pressing pressure of the second-stage pressing rod is 5.8 MPa, and the pressing temperature is 64°C; the pressing pressure of the third-stage pressing rod is 6.2 MPa, and the pressing temperature is 66°C; the pressing pressure of the fourth-stage pressing rod is 6.5 MPa, and the pressing temperature is 67°C; the pressing pressure of the fifth-stage pressing rod is 6.8 MPa, and the pressing temperature is 68°C; the pressing pressure of the sixth-stage pressing rod is 7.2 MPa, and the pressing temperature is 69°C; the pressing pressure of the seventh-stage pressing rod is 7.5 MPa, and the pressing temperature is 70°C; the pressing pressure of the eighth-stage pressing rod is 8 MPa, and the pressing temperature is 72°C; the pressing pressure of the ninth-stage pressing rod is 8.8 MPa, and the pressing temperature is 74°C; the pressing pressure of the tenth-stage pressing rod is 9.5 MPa, and the pressing temperature is 75°C. Place the polymer thin sheet in an oven and set the heating temperature to 125°C to dry and remove petroleum ether; further send it into a radiation box for radiation cross-linking treatment with a radiation intensity of 12 kGy to obtain a cross-linked polytetrafluoroethylene film; uniformly coat a solution obtained by dissolving poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] at a concentration of 15 mg / mL in chlorobenzene on the cross-linked polytetrafluoroethylene film and anneal it at 108°C for 8 minutes to obtain a polymer film.

[0086] Further, place the stretched polymer film in liquid ammonia for 4 minutes to cool and modify the polymer film.

[0087] Mix lead zirconate titanate powder and binder in a mass ratio of 95:5 and stir evenly, and perform pre-pressing treatment under a pressure of 10 MPa to obtain a pre-pressed block. Grind the pre-pressed block and sieve it, then inject it into a mold and dry-press it into shape under a pressure of 18 MPa to obtain a blank. Among them, the lead zirconate titanate powder is obtained by mixing Pb3O4 powder, GeO2 powder, NiO powder, BaCO3 powder, ZrO2 powder, SnO2 powder, and TiO2 powder in a mass ratio of 8:0.3:0.5:1.5:5:3.6:1.1, and the binder is obtained by mixing glycerin, alcohol, and distilled water in a mass ratio of 16:4:80.

[0088] Perform high-temperature sintering on the blank to obtain a piezoelectric ceramic body. Among them, first heat the blank from room temperature to 960°C and hold for 0.5 hour, and then heat the blank from the current temperature to 1120°C and hold for 3.5 hours to complete the sintering operation.

[0089] The piezoelectric ceramic body is ground, and the ground piezoelectric ceramic powder is sieved through a 2500-mesh sieve. The sieved piezoelectric ceramic powder is mixed with a viscous solvent to obtain a piezoelectric ceramic powder suspension; wherein, the viscous solvent is cyclohexane. The mass ratio of the piezoelectric ceramic powder in the piezoelectric ceramic powder suspension is 1.5%.

[0090] The piezoelectric ceramic powder suspension is evenly coated on both surfaces of the modified polymer film, and then the modified polymer film is placed in an oven and the heating temperature is set to 98 °C to volatilize the viscous solvent; wherein, the coating amount of the piezoelectric ceramic powder suspension on the surface of the modified polymer film is 120 ml / m 2 .

[0091] The initial diaphragm obtained in the above steps is polarized under a thermal environment of 165 °C and a polarization electric field in a fixed field strength direction. Specifically, the electric field strength of the polarization electric field is 220 V / m, wherein the polarization duration is 30 minutes. After the polarization is completed, a diaphragm with a piezoelectric ceramic coating can be obtained.

[0092] Example 5

[0093] The polymer film is longitudinally stretched at 210 °C, and the longitudinal stretching ratio is 6.8; then it is transversely stretched at 170 °C, and the stretching ratio is 4.

[0094] Specifically, the method for preparing the polymer film includes the following steps: Mix polytetrafluoroethylene powder, petroleum ether, and KH-550 silane coupling agent (γ-aminopropyltriethoxysilane) in a reaction kettle in a mass ratio of 10:1.8:0.3, and seal and cure at 45°C for 6.5 hours to obtain a paste; Flatten and extend the above paste through a ten-stage pressing rod to obtain a polymer thin sheet. The pressing pressure of the first-stage pressing rod is 5.5 MPa, and the pressing temperature is 62°C; The pressing pressure of the second-stage pressing rod is 5.8 MPa, and the pressing temperature is 64°C; The pressing pressure of the third-stage pressing rod is 6.2 MPa, and the pressing temperature is 66°C; The pressing pressure of the fourth-stage pressing rod is 6.5 MPa, and the pressing temperature is 67°C; The pressing pressure of the fifth-stage pressing rod is 6.8 MPa, and the pressing temperature is 68°C; The pressing pressure of the sixth-stage pressing rod is 7.2 MPa, and the pressing temperature is 69°C; The pressing pressure of the seventh-stage pressing rod is 7.5 MPa, and the pressing temperature is 70°C; The pressing pressure of the eighth-stage pressing rod is 8 MPa, and the pressing temperature is 72°C; The pressing pressure of the ninth-stage pressing rod is 8.8 MPa, and the pressing temperature is 74°C; The pressing pressure of the tenth-stage pressing rod is 9.5 MPa, and the pressing temperature is 75°C. Place the polymer thin sheet in an oven and set the heating temperature to 125°C to dry and remove petroleum ether; Further send it into a radiation box for radiation cross-linking treatment with a radiation intensity of 12 kGy to obtain a cross-linked polytetrafluoroethylene film; A solution obtained by dissolving poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] in chlorobenzene at a concentration of 15 mg / mL is uniformly coated on the cross-linked polytetrafluoroethylene film and annealed at 108°C for 8 minutes to obtain a polymer film.

[0095] Further, place the stretched polymer film in liquid ammonia for 4 minutes to cool and modify the polymer film.

[0096] Mix lead zirconate titanate powder and binder in a mass ratio of 95:5 and stir evenly, and perform pre-pressing treatment under a pressure of 10 MPa to obtain a pre-pressed block. Grind the pre-pressed block and sieve it, then inject it into a mold and dry-press it into shape under a pressure of 18 MPa to obtain a blank. Among them, the lead zirconate titanate powder is obtained by mixing Pb3O4 powder, GeO2 powder, NiO powder, BaCO3 powder, ZrO2 powder, SnO2 powder, and TiO2 powder in a mass ratio of 9:0.2:0.3:1.2:4.8:3.5:1, and the binder is obtained by mixing glycerol, alcohol, and distilled water in a mass ratio of 16:4:80.

[0097] Perform high-temperature sintering on the blank to obtain a piezoelectric ceramic body. Among them, first heat the blank from room temperature to 960°C and hold for 0.5 hour, and then heat the blank from the current temperature to 1120°C and hold for 3.5 hours to complete the sintering operation.

[0098] The piezoelectric ceramic body is ground, and the ground piezoelectric ceramic powder is sieved through a 2500-mesh sieve. The sieved piezoelectric ceramic powder is mixed with a viscous solvent to obtain a piezoelectric ceramic powder suspension; wherein, the viscous solvent is cyclohexane. The mass ratio of the piezoelectric ceramic powder in the piezoelectric ceramic powder suspension is 1.5%.

[0099] The piezoelectric ceramic powder suspension is uniformly coated on both surfaces of the modified polymer film, and then the modified polymer film is placed in an oven and the heating temperature is set at 98 °C to volatilize the viscous solvent; wherein, the coating amount of the piezoelectric ceramic powder suspension on the surface of the modified polymer film is 120 ml / m 2 .

[0100] The initial diaphragm obtained in the above steps is polarized under a thermal environment of 165 °C and a polarization electric field with a fixed field strength direction. Specifically, the electric field strength of the polarization electric field is 220 V / m, wherein the polarization duration is 30 minutes. After the polarization is completed, a diaphragm with a piezoelectric ceramic coating can be obtained.

[0101] Example 6

[0102] The polymer film is longitudinally stretched at 210 °C, and the longitudinal stretching ratio is 6.8; then it is transversely stretched at 170 °C, and the stretching ratio is 4.

[0103] Specifically, the preparation method of the polymer film includes the following steps: Mix polytetrafluoroethylene powder, petroleum ether, and KH-550 silane coupling agent (γ-aminopropyltriethoxysilane) in a reaction kettle in a mass ratio of 10:1.8:0.3, and seal and cure at 45°C for 6.5 hours to obtain a paste; Flatten and extend the above paste through a ten-stage pressure bar to obtain a polymer thin sheet. The pressing pressure of the first-stage pressure bar is 5.5 MPa and the pressing temperature is 62°C; The pressing pressure of the second-stage pressure bar is 5.8 MPa and the pressing temperature is 64°C; The pressing pressure of the third-stage pressure bar is 6.2 MPa and the pressing temperature is 66°C; The pressing pressure of the fourth-stage pressure bar is 6.5 MPa and the pressing temperature is 67°C; The pressing pressure of the fifth-stage pressure bar is 6.8 MPa and the pressing temperature is 68°C; The pressing pressure of the sixth-stage pressure bar is 7.2 MPa and the pressing temperature is 69°C; The pressing pressure of the seventh-stage pressure bar is 7.5 MPa and the pressing temperature is 70°C; The pressing pressure of the eighth-stage pressure bar is 8 MPa and the pressing temperature is 72°C; The pressing pressure of the ninth-stage pressure bar is 8.8 MPa and the pressing temperature is 74°C; The pressing pressure of the tenth-stage pressure bar is 9.5 MPa and the pressing temperature is 75°C. Place the polymer thin sheet in an oven and set the heating temperature to 125°C to dry and remove petroleum ether; Further send it into a radiation box for radiation cross-linking treatment with a radiation intensity of 12 kGy to obtain a cross-linked polytetrafluoroethylene film; A solution obtained by dissolving poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] in chlorobenzene at a concentration of 15 mg / mL is uniformly coated on the cross-linked polytetrafluoroethylene film and annealed at 108°C for 8 minutes to obtain a polymer film.

[0104] Further, place the stretched polymer film in liquid ammonia for 4 minutes to cool and modify the polymer film.

[0105] Mix lead zirconate titanate powder and binder in a mass ratio of 95:5 and stir evenly, and perform pre-pressing treatment under a pressure of 10 MPa to obtain a pre-pressed block. After grinding the pre-pressed block and passing it through a sieve, inject it into a mold and dry-press it into shape under a pressure of 18 MPa to obtain a blank. Among them, the lead zirconate titanate powder is obtained by mixing Pb3O4 powder, GeO2 powder, NiO powder, BaCO3 powder, ZrO2 powder, SnO2 powder, and TiO2 powder in a mass ratio of 8:0.4:0.6:1.2:5:3.6:1, and the binder is obtained by mixing glycerol, alcohol, and distilled water in a mass ratio of 16:4:80.

[0106] Perform high-temperature sintering on the blank to obtain a piezoelectric ceramic body. Among them, first heat the blank from room temperature to 960°C and keep it for 0.5 hour, and then heat the blank from the current temperature to 1120°C and keep it for 3.5 hours to complete the sintering operation.

[0107] The piezoelectric ceramic body is ground, and the ground piezoelectric ceramic powder is sieved through a 2500-mesh sieve. The sieved piezoelectric ceramic powder is mixed with a viscous solvent to obtain a piezoelectric ceramic powder suspension; wherein, the viscous solvent is cyclohexane. The mass ratio of the piezoelectric ceramic powder in the piezoelectric ceramic powder suspension is 1.5%.

[0108] The piezoelectric ceramic powder suspension is evenly coated on both surfaces of the modified polymer film, and then the modified polymer film is placed in an oven and the heating temperature is set at 98 °C to volatilize the viscous solvent; wherein, the coating amount of the piezoelectric ceramic powder suspension on the surface of the modified polymer film is 120 ml / m 2 .

[0109] The initial diaphragm obtained in the above steps is polarized under a thermal environment of 165 °C and a polarization electric field with a fixed field strength direction. Specifically, the electric field strength of the polarization electric field is 220 V / m, wherein the polarization duration is 30 minutes. After polarization is completed, a diaphragm with a piezoelectric ceramic coating can be obtained.

[0110] Example 7

[0111] The polymer film is longitudinally stretched at 210 °C with a longitudinal stretching ratio of 6.8; then it is transversely stretched at 170 °C with a stretching ratio of 4.

[0112] Specifically, the preparation method of the polymer film includes the following steps: Mix polytetrafluoroethylene powder, petroleum ether, and KH-550 silane coupling agent (γ-aminopropyltriethoxysilane) in a reaction kettle in a mass ratio of 10:1.8:0.3, and seal and cure at 45°C for 6.5 hours to obtain a paste; Flatten and extend the above paste through a ten-stage pressing rod to obtain a polymer thin sheet. The pressing pressure of the first-stage pressing rod is 5.5 MPa and the pressing temperature is 62°C; The pressing pressure of the second-stage pressing rod is 5.8 MPa and the pressing temperature is 64°C; The pressing pressure of the third-stage pressing rod is 6.2 MPa and the pressing temperature is 66°C; The pressing pressure of the fourth-stage pressing rod is 6.5 MPa and the pressing temperature is 67°C; The pressing pressure of the fifth-stage pressing rod is 6.8 MPa and the pressing temperature is 68°C; The pressing pressure of the sixth-stage pressing rod is 7.2 MPa and the pressing temperature is 69°C; The pressing pressure of the seventh-stage pressing rod is 7.5 MPa and the pressing temperature is 70°C; The pressing pressure of the eighth-stage pressing rod is 8 MPa and the pressing temperature is 72°C; The pressing pressure of the ninth-stage pressing rod is 8.8 MPa and the pressing temperature is 74°C; The pressing pressure of the tenth-stage pressing rod is 9.5 MPa and the pressing temperature is 75°C. Place the polymer thin sheet in an oven and set the heating temperature to 125°C to dry and remove petroleum ether; Further send it into a radiation box for radiation cross-linking treatment with a radiation intensity of 12 kGy to obtain a cross-linked polytetrafluoroethylene film; A solution obtained by dissolving poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] in chlorobenzene at a concentration of 10 mg / mL is uniformly coated on the cross-linked polytetrafluoroethylene film and annealed at 108°C for 8 minutes to obtain a polymer film.

[0113] Further, place the stretched polymer film in liquid ammonia for 4 minutes to cool and modify the polymer film.

[0114] Mix lead zirconate titanate powder and binder in a mass ratio of 95:5 and stir evenly, and perform pre-pressing treatment under a pressure of 10 MPa to obtain a pre-pressed block. After grinding the pre-pressed block and sieving, inject it into a mold and dry-press it into shape under a pressure of 18 MPa to obtain a blank. Among them, the lead zirconate titanate powder is obtained by mixing Pb3O4 powder, GeO2 powder, NiO powder, BaCO3 powder, ZrO2 powder, SnO2 powder, and TiO2 powder in a mass ratio of 8:0.3:0.5:1.5:5:3.6:1.1, and the binder is obtained by mixing glycerin, alcohol, and distilled water in a mass ratio of 16:4:80.

[0115] Perform high-temperature sintering on the blank to obtain a piezoelectric ceramic body. Among them, first heat the blank from room temperature to 960°C and keep it for 0.5 hour, and then heat the blank from the current temperature to 1120°C and keep it for 3.5 hours to complete the sintering operation.

[0116] Grind the piezoelectric ceramic body, and screen the obtained piezoelectric ceramic powder through a 2500-mesh sieve. Mix the piezoelectric ceramic powder obtained after sieving with a viscous solvent to obtain a piezoelectric ceramic powder suspension; wherein, the viscous solvent is cyclohexane. The mass ratio of the piezoelectric ceramic powder in the piezoelectric ceramic powder suspension is 1.5%.

[0117] Uniformly coat the two surfaces of the modified polymer film with the piezoelectric ceramic powder suspension, and then place the modified polymer film in an oven and set the heating temperature to 98 °C to volatilize the viscous solvent; wherein, the coating amount of the piezoelectric ceramic powder suspension on the surface of the modified polymer film is 120 ml / m 2 .

[0118] Place the initial diaphragm obtained in the above steps in a thermal environment at 165 °C and a polarization electric field with a fixed field strength direction for polarization. Specifically, the electric field strength of the polarization electric field is 220 V / m, wherein the polarization duration is 30 minutes. After completion of polarization, a diaphragm with a piezoelectric ceramic coating can be obtained.

[0119] Example 8

[0120] Longitudinally stretch the polymer film at 210 °C, and the longitudinal stretching ratio is 6.8; then transversely stretch it at 170 °C, and the stretching ratio is 4.

[0121] Specifically, the preparation method of the polymer film includes the following steps: Mix polytetrafluoroethylene powder, petroleum ether, and KH-550 silane coupling agent (γ-aminopropyltriethoxysilane) in a reaction kettle in a mass ratio of 10:1.8:0.3, and seal and cure at 45°C for 6.5 hours to obtain a paste; Flatten and extend the above paste through a ten-stage pressing rod to obtain a polymer sheet. The pressing pressure of the first-stage pressing rod is 5.5 MPa and the pressing temperature is 62°C; The pressing pressure of the second-stage pressing rod is 5.8 MPa and the pressing temperature is 64°C; The pressing pressure of the third-stage pressing rod is 6.2 MPa and the pressing temperature is 66°C; The pressing pressure of the fourth-stage pressing rod is 6.5 MPa and the pressing temperature is 67°C; The pressing pressure of the fifth-stage pressing rod is 6.8 MPa and the pressing temperature is 68°C; The pressing pressure of the sixth-stage pressing rod is 7.2 MPa and the pressing temperature is 69°C; The pressing pressure of the seventh-stage pressing rod is 7.5 MPa and the pressing temperature is 70°C; The pressing pressure of the eighth-stage pressing rod is 8 MPa and the pressing temperature is 72°C; The pressing pressure of the ninth-stage pressing rod is 8.8 MPa and the pressing temperature is 74°C; The pressing pressure of the tenth-stage pressing rod is 9.5 MPa and the pressing temperature is 75°C. Place the polymer sheet in an oven and set the heating temperature to 125°C to dry and remove petroleum ether; Further send it into a radiation box for radiation cross-linking treatment with a radiation intensity of 12 kGy to obtain a cross-linked polytetrafluoroethylene film; A solution obtained by dissolving poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] at a concentration of 10 mg / mL in chlorobenzene is uniformly coated on the cross-linked polytetrafluoroethylene film and annealed at 108°C for 8 minutes to obtain a polymer film.

[0122] Further, place the stretched polymer film in liquid ammonia for 4 minutes to cool and modify the polymer film.

[0123] Mix lead zirconate titanate powder and binder in a mass ratio of 95:5 and stir evenly, and perform pre-pressing treatment under a pressure of 10 MPa to obtain a pre-pressed block. After grinding the pre-pressed block and sieving, inject it into a mold and dry-press it into shape under a pressure of 18 MPa to obtain a blank. Among them, the lead zirconate titanate powder is obtained by mixing Pb3O4 powder, GeO2 powder, NiO powder, BaCO3 powder, ZrO2 powder, SnO2 powder, and TiO2 powder in a mass ratio of 9:0.2:0.3:1.2:4.8:3.5:1, and the binder is obtained by mixing glycerol, alcohol, and distilled water in a mass ratio of 16:4:80.

[0124] Perform high-temperature sintering on the blank to obtain a piezoelectric ceramic body. Among them, first heat the blank from room temperature to 960°C and hold for 0.5 hour, and then heat the blank from the current temperature to 1120°C and hold for 3.5 hours to complete the sintering operation.

[0125] The piezoelectric ceramic body is ground, and the ground piezoelectric ceramic powder is sieved through a 2500-mesh sieve. The sieved piezoelectric ceramic powder is mixed with a viscous solvent to obtain a piezoelectric ceramic powder suspension; wherein, the viscous solvent is cyclohexane. The mass ratio of the piezoelectric ceramic powder in the piezoelectric ceramic powder suspension is 1.5%.

[0126] The piezoelectric ceramic powder suspension is evenly coated on both surfaces of the modified polymer film, and then the modified polymer film is placed in an oven and the heating temperature is set at 98 °C to volatilize the viscous solvent; wherein, the coating amount of the piezoelectric ceramic powder suspension on the surface of the modified polymer film is 120 ml / m 2 .

[0127] The initial diaphragm obtained in the above steps is polarized under a thermal environment of 165 °C and a polarization electric field with a fixed field strength direction. Specifically, the electric field strength of the polarization electric field is 220 V / m, wherein the polarization duration is 30 minutes. After the polarization is completed, a diaphragm with a piezoelectric ceramic coating can be obtained.

[0128] Example 9

[0129] The polymer film is longitudinally stretched at 210 °C, and the longitudinal stretching ratio is 6.8; then it is transversely stretched at 170 °C, and the stretching ratio is 4.

[0130] Specifically, the preparation method of the polymer film includes the following steps: Mix polytetrafluoroethylene powder, petroleum ether, and KH-550 silane coupling agent (γ-aminopropyltriethoxysilane) in a reaction kettle in a mass ratio of 10:1.8:0.3, and seal and cure at 45°C for 6.5 hours to obtain a paste; flatten and extend the above paste through a ten-stage pressing rod to obtain a polymer thin sheet. The pressing pressure of the first-stage pressing rod is 5.5 MPa and the pressing temperature is 62°C; the pressing pressure of the second-stage pressing rod is 5.8 MPa and the pressing temperature is 64°C; the pressing pressure of the third-stage pressing rod is 6.2 MPa and the pressing temperature is 66°C; the pressing pressure of the fourth-stage pressing rod is 6.5 MPa and the pressing temperature is 67°C; the pressing pressure of the fifth-stage pressing rod is 6.8 MPa and the pressing temperature is 68°C; the pressing pressure of the sixth-stage pressing rod is 7.2 MPa and the pressing temperature is 69°C; the pressing pressure of the seventh-stage pressing rod is 7.5 MPa and the pressing temperature is 70°C; the pressing pressure of the eighth-stage pressing rod is 8 MPa and the pressing temperature is 72°C; the pressing pressure of the ninth-stage pressing rod is 8.8 MPa and the pressing temperature is 74°C; the pressing pressure of the tenth-stage pressing rod is 9.5 MPa and the pressing temperature is 75°C. Place the polymer thin sheet in an oven and set the heating temperature to 125°C to dry and remove petroleum ether; further send it into a radiation box for radiation cross-linking treatment with a radiation intensity of 12 kGy to obtain a cross-linked polytetrafluoroethylene film; uniformly coat the solution obtained by dissolving poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] in chlorobenzene at a concentration of 10 mg / mL on the cross-linked polytetrafluoroethylene film and anneal at 108°C for 8 minutes to obtain a polymer film.

[0131] Further, place the stretched polymer film in liquid ammonia for 4 minutes to cool and modify the polymer film.

[0132] Mix lead zirconate titanate powder and binder in a mass ratio of 95:5 and stir evenly, and perform pre-pressing treatment under a pressure of 10 MPa to obtain a pre-pressed block. Grind the pre-pressed block and sieve it, then inject it into a mold and dry-press it into shape under a pressure of 18 MPa to obtain a blank. Among them, the lead zirconate titanate powder is obtained by mixing Pb3O4 powder, GeO2 powder, NiO powder, BaCO3 powder, ZrO2 powder, SnO2 powder, and TiO2 powder in a mass ratio of 8:0.4:0.6:1.2:5:3.6:1, and the binder is obtained by mixing glycerol, alcohol, and distilled water in a mass ratio of 16:4:80.

[0133] Perform high-temperature sintering on the blank to obtain a piezoelectric ceramic body. Specifically, first heat the blank from room temperature to 960°C and keep it for 0.5 hour, and then heat the blank from the current temperature to 1120°C and keep it for 3.5 hours to complete the sintering operation.

[0134] The piezoelectric ceramic body is ground, and the ground piezoelectric ceramic powder is sieved through a 2500-mesh sieve. The sieved piezoelectric ceramic powder is mixed with a viscous solvent to obtain a piezoelectric ceramic powder suspension; wherein, the viscous solvent is cyclohexane. The mass ratio of the piezoelectric ceramic powder in the piezoelectric ceramic powder suspension is 1.5%.

[0135] The piezoelectric ceramic powder suspension is evenly coated on both surfaces of the modified polymer film, and then the modified polymer film is placed in an oven and the heating temperature is set to 98 °C to volatilize the viscous solvent; wherein, the coating amount of the piezoelectric ceramic powder suspension on the surface of the modified polymer film is 120 ml / m 2 .

[0136] The initial diaphragm obtained in the above steps is polarized under a thermal environment of 165 °C and a polarization electric field with a fixed field strength direction. Specifically, the electric field strength of the polarization electric field is 220 V / m, wherein the polarization duration is 30 minutes. After polarization, a diaphragm with a piezoelectric ceramic coating can be obtained.

[0137] Comparative Example 1

[0138] Aluminum oxide powder and binder are mixed and stirred evenly according to a mass ratio of 95:5, and pre-pressed under a pressure of 10 MPa to obtain a pre-pressed block. The pre-pressed block is ground and sieved, and then injected into a mold and dry-pressed into a blank under a pressure of 18 MPa. The binder is obtained by mixing glycerol, alcohol and distilled water according to a mass ratio of 16:4:80. The blank is subjected to high-temperature sintering and then ground, and the ground aluminum oxide solid powder is sieved through a 2500-mesh sieve. The sieved aluminum oxide solid powder is mixed with a viscous solvent to obtain an aluminum oxide solid powder suspension.

[0139] The poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] film is longitudinally stretched at 210 °C, and the longitudinal stretching ratio is 6.8; then it is transversely stretched at 170 °C, and the stretching ratio is 4.

[0140] The aluminum oxide solid powder suspension is evenly coated on both surfaces of the stretched poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] film, and then the poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] film is placed in an oven and heated to volatilize the viscous solvent to obtain an initial diaphragm.

[0141] The initial diaphragm obtained in the above steps is polarized under a thermal environment of 165 °C and a polarization electric field with a fixed field strength direction. Specifically, the electric field strength of the polarization electric field is 220 V / m, wherein the polarization duration is 30 minutes to obtain an aluminum oxide diaphragm.

[0142] Comparative Example 2

[0143] Mix alumina powder and binder in a mass ratio of 95:5 and stir evenly. Then, perform pre-pressing treatment under a pressure of 10 MPa to obtain a pre-pressed block. Grind the pre-pressed block and sieve it, and then inject it into a mold and dry-press it into shape under a pressure of 18 MPa to obtain a green body. The binder is obtained by mixing glycerol, alcohol, and distilled water in a mass ratio of 16:4:80. After high-temperature sintering the green body, grind it, and sieve the obtained alumina solid powder through a 2500-mesh sieve.

[0144] Mix polytetrafluoroethylene powder, petroleum ether, and alumina solid powder evenly in a reaction kettle in a mass ratio of 10:1.8:0.3, and seal and cure at 45 °C for 6.5 hours to obtain a paste; flatten and extend the above paste through a ten-stage pressing rod to obtain a polymer thin film. The pressing pressure of the first-stage pressing rod is 5.5 MPa and the pressing temperature is 62 °C; the pressing pressure of the second-stage pressing rod is 5.8 MPa and the pressing temperature is 64 °C; the pressing pressure of the third-stage pressing rod is 6.2 MPa and the pressing temperature is 66 °C; the pressing pressure of the fourth-stage pressing rod is 6.5 MPa and the pressing temperature is 67 °C; the pressing pressure of the fifth-stage pressing rod is 6.8 MPa and the pressing temperature is 68 °C; the pressing pressure of the sixth-stage pressing rod is 7.2 MPa and the pressing temperature is 69 °C; the pressing pressure of the seventh-stage pressing rod is 7.5 MPa and the pressing temperature is 70 °C; the pressing pressure of the eighth-stage pressing rod is 8 MPa and the pressing temperature is 72 °C; the pressing pressure of the ninth-stage pressing rod is 8.8 MPa and the pressing temperature is 74 °C; the pressing pressure of the tenth-stage pressing rod is 9.5 MPa and the pressing temperature is 75 °C. Place the polymer thin film in an oven and set the heating temperature to 125 °C to dry and remove the petroleum ether to obtain an initial diaphragm.

[0145] Perform longitudinal stretching on the above initial diaphragm at 210 °C, and the longitudinal stretching ratio is 6.8; then perform transverse stretching at 170 °C, and the stretching ratio is 4.

[0146] Place the initial diaphragm obtained in the above steps in a thermal environment at 165 °C and a polarization electric field with a fixed field strength direction for polarization. Specifically, the electric field strength of the polarization electric field is 220 V / m, and the polarization duration is 30 minutes to obtain an alumina diaphragm.

[0147] Comparative Example 3

[0148] Mix alumina powder and binder in a mass ratio of 95:5 and stir evenly. Then, perform pre-pressing treatment under a pressure of 10 MPa to obtain a pre-pressed block. Grind the pre-pressed block and sieve it, then inject it into a mold and perform dry pressing at a pressure of 18 MPa to obtain a green body. The binder is obtained by mixing glycerol, alcohol, and distilled water in a mass ratio of 16:4:80. After high-temperature sintering the green body, grind it, and sieve the obtained alumina solid powder through a 2500-mesh sieve. Mix the sieved alumina solid powder with a viscous solvent to obtain an alumina solid powder suspension.

[0149] The polytetrafluoroethylene membrane is longitudinally stretched at 210 °C with a longitudinal stretching ratio of 6.8; then it is transversely stretched at 170 °C with a stretching ratio of 4.

[0150] Specifically, the preparation method of the polytetrafluoroethylene membrane includes the following steps: Mix polytetrafluoroethylene powder, petroleum ether, and KH-550 silane coupling agent (γ-aminopropyltriethoxysilane) in a mass ratio of 10:1.8:0.3 in a reaction kettle and mix evenly. Seal and cure at 45 °C for 6.5 hours to obtain a paste; Flatten and extend the above paste through a ten-stage pressure rod to obtain a polymer thin sheet. The pressing pressure of the first-stage pressure rod is 5.5 MPa and the pressing temperature is 62 °C; The pressing pressure of the second-stage pressure rod is 5.8 MPa and the pressing temperature is 64 °C; The pressing pressure of the third-stage pressure rod is 6.2 MPa and the pressing temperature is 66 °C; The pressing pressure of the fourth-stage pressure rod is 6.5 MPa and the pressing temperature is 67 °C; The pressing pressure of the fifth-stage pressure rod is 6.8 MPa and the pressing temperature is 68 °C; The pressing pressure of the sixth-stage pressure rod is 7.2 MPa and the pressing temperature is 69 °C; The pressing pressure of the seventh-stage pressure rod is 7.5 MPa and the pressing temperature is 70 °C; The pressing pressure of the eighth-stage pressure rod is 8 MPa and the pressing temperature is 72 °C; The pressing pressure of the ninth-stage pressure rod is 8.8 MPa and the pressing temperature is 74 °C; The pressing pressure of the tenth-stage pressure rod is 9.5 MPa and the pressing temperature is 75 °C. Place the polymer thin sheet in an oven and set the heating temperature to 125 °C to dry and remove petroleum ether to obtain a polytetrafluoroethylene membrane.

[0151] Evenly coat the two surfaces of the stretched polytetrafluoroethylene membrane with the alumina solid powder suspension, and then place the polytetrafluoroethylene membrane in an oven to heat and volatilize the viscous solvent to obtain an initial diaphragm.

[0152] Place the initial diaphragm obtained in the above steps in a thermal environment of 165 °C and a polarization electric field with a fixed field strength direction for polarization. Specifically, the electric field strength of the polarization electric field is 220 V / m, and the polarization duration is 30 minutes to obtain an alumina diaphragm.

[0153] Test Example 1

[0154] Conduction efficiency test: The ion conduction efficiency of the diaphragms obtained in Examples 4-9 of the present invention and Comparative Examples 1-3 was tested. A positive electrode material layer and a negative electrode material layer were disposed on both sides of the diaphragms in the above-mentioned examples and the above-mentioned comparative examples. The positive electrode material layer was rich in lithium ion salt, and the negative electrode material layer was rich in lithium-silicon composite active material. A silver metal sheet was disposed on the outer side of the positive electrode material layer as the positive electrode contact electrode sheet, and a silver metal sheet was disposed on the outer side of the negative electrode material layer as the negative electrode contact electrode sheet, thereby combining to form a rechargeable battery assembly; a rated voltage of 5V was applied to the two contact electrode sheets and the current between the positive electrode and the negative electrode was measured to test the conduction efficiency of the diaphragm. The results obtained are shown in Table 1.

[0155] Table 1

[0156] Serial number Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Current (mA) 453 462 450 475 481 464 Serial number Comparative example 1 Comparative example 2 Comparative example 3 Current (mA) 421 407 434

[0157] Through test comparison, it was found that by stretching the polymer film and then soaking it in liquid ammonia for modification, the film through-holes in the polymer film could be tightened and fixed, thereby maintaining the pore diameter of the film through-holes and improving the ion conduction efficiency.

[0158] Test Example 2

[0159] Battery capacity test: The battery capacity of the diaphragms obtained in Examples 1-9 of the present invention and Comparative Examples 1-3 was tested. A positive electrode material layer and a negative electrode material layer were disposed on both sides of the diaphragms in the above-mentioned examples and the above-mentioned comparative examples. A silver metal sheet was disposed on the outer side of the positive electrode material layer as the positive electrode contact electrode sheet, and a silver metal sheet was disposed on the outer side of the negative electrode material layer as the negative electrode contact electrode sheet, thereby combining to form a rechargeable battery assembly; a pulsed direct current with a rated voltage of 5V was applied to the two contact electrode sheets to repeatedly charge the rechargeable battery assembly. The pulse frequency was 40 kHz, and the number of charging times was 500 times. The capacity ratio of the current battery capacity to the initial battery capacity of the rechargeable battery assembly after 500 times of charging was measured. The results obtained are shown in Table 2.

[0160] Table 2

[0161] Serial number Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Capacity ratio 0.937 0.933 0.946 0.956 0.952 0.957 Serial number Example 7 Example 8 Example 9 Comparative example 1 Comparative example 2 Comparative example 3 Capacity ratio 0.946 0.942 0.950 0.733 0.695 0.726

[0162] Through test comparison, it was found that by adding piezoelectric ceramic particles on the surface of the polymer film, when a pulsed direct current was applied for charging, vibrations could be generated by the piezoelectric ceramic particles and the generation of dendrites could be effectively avoided, thereby greatly reducing the battery capacity loss of the rechargeable battery after repeated charging and improving the utilization efficiency of the rechargeable battery.

[0163] In the diaphragm with piezoelectric ceramic coating and its manufacturing method provided by the embodiments of the present invention, the method includes stretching a polymer film and then immersing it in liquid ammonia for cooling to obtain a modified polymer film; mixing piezoelectric ceramic powder with an adhesive and performing pre-pressing treatment to obtain a pre-pressed block, grinding it, sieving it, injecting it into a mold, and performing dry pressing to form a blank. The blank is sintered at a high temperature to obtain a piezoelectric ceramic body, which is ground and sieved and then mixed with a viscous solvent to form a piezoelectric ceramic powder suspension. The suspension is evenly coated on the surface of the modified polymer film and heated. The obtained diaphragm is polarized in an environment of 140 - 180 °C and a polarization electric field with a fixed field strength direction to obtain a diaphragm with piezoelectric ceramic coating. By using the above method, the polymer film is stretched and cooled and modified to form film through-holes on the polymer film. Then, piezoelectric ceramic particles are laid on the surface of the polymer film to obtain a diaphragm with piezoelectric ceramic coating. A direct current pulse current is passed through to drive the piezoelectric ceramic particles on the diaphragm to generate vibrations, and the diaphragm generates mechanical expansion and contraction to break the metal ion crystals on the diaphragm through mechanical force, thereby effectively preventing the generation of crystal nuclei inside the battery electrode sheet.

[0164] As described above, the above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A manufacturing method of a diaphragm with a piezoelectric ceramic coating, characterized in that, The method includes: longitudinally stretching the polymer film at 165 - 235°C with a longitudinal stretching ratio of 4 - 9; then transversely stretching it at 135 - 185°C with a stretching ratio of 2.5 - 5; immersing the stretched polymer film in liquid ammonia for 2 - 5 minutes to cool the polymer film to obtain a modified polymer film; mixing piezoelectric ceramic powder and binder in a mass ratio of (92 - 96):(2 - 5), stirring evenly, and performing pre - pressing treatment under a pressure of 6 - 15 MPa to obtain a pre - pressed block. After grinding the pre - pressed block and sieving, it is injected into a mold and dry - pressed into a blank under a pressure of 8 - 22 MPa; sintering the blank at 900 - 1200°C for 2 - 5 hours to obtain a piezoelectric ceramic body; grinding the piezoelectric ceramic body and sieving it, and mixing the sieved piezoelectric ceramic powder with a viscous solvent to form a piezoelectric ceramic powder suspension; uniformly coating the piezoelectric ceramic powder suspension on the surface of the modified polymer film, and placing the modified polymer film in an oven and setting the heating temperature at 95 - 110°C to volatilize the viscous solvent to obtain an initial diaphragm; polarizing the initial diaphragm in an environment of 140 - 180°C and a polarization electric field with a fixed field - strength direction to obtain a diaphragm with a piezoelectric ceramic coating.

2. The manufacturing method of the diaphragm with piezoelectric ceramic coating according to claim 1, characterized in that, The preparation method of the polymer film includes: mixing polytetrafluoroethylene powder, petroleum ether, and silane coupling agent in a mass ratio of 10:2.2:(0.2 - 0.5) evenly in a reaction kettle, and sealing and curing at 40 - 50°C for 6 - 8 hours to obtain a paste; flattening and extending the above - mentioned paste under a pressure of 5 - 9.5 MPa through a pressure bar to form a polymer sheet; the temperature for flattening and extending is 62 - 75°C; placing the polymer sheet in an oven and setting the heating temperature at 120 - 130°C to dry and remove petroleum ether; further sending it into a radiation box for radiation cross - linking treatment to obtain a cross - linked polytetrafluoroethylene film; uniformly coating a solution obtained by dissolving poly[bis(4 - phenyl)(2,4,6 - trimethylphenyl)amine] in chlorobenzene at a concentration of 6 - 25 mg / mL on the cross - linked polytetrafluoroethylene film and performing annealing treatment to obtain a polymer film.

3. The manufacturing method of the diaphragm with piezoelectric ceramic coating according to claim 1 or 2, characterized in that, The piezoelectric ceramic powder is obtained by mixing Pb3O4 powder, GeO2 powder, NiO powder, BaCO3 powder, ZrO2 powder, SnO2 powder, and TiO2 powder in a mass ratio of (7.5 - 9.5):(0.2 - 0.5):(0.3 - 0.8):(0.6 - 1.8):(4.6 - 5):(3.2 - 3.8):(0.6 - 1.3).

4. The manufacturing method of the diaphragm with piezoelectric ceramic coating according to claim 3, characterized in that, The viscous solvent is one or a combination of isopropanol, cyclohexane, and methylcyclohexanol.

5. The manufacturing method of the diaphragm with piezoelectric ceramic coating according to claim 3, characterized in that, The step of grinding the piezoelectric ceramic body and then sieving it includes: sieving the ground piezoelectric ceramic powder through 1200 - 4000 meshes.

6. The manufacturing method of the diaphragm with piezoelectric ceramic coating according to claim 5, characterized in that, The mass ratio of the piezoelectric ceramic powder in the piezoelectric ceramic powder suspension is 0.8 - 2%.

7. The manufacturing method of the diaphragm with piezoelectric ceramic coating according to claim 6, characterized in that, The coating amount of the piezoelectric ceramic powder suspension on the surface of the modified polymer film is 45 - 200 ml / m 2 .

8. The manufacturing method of the diaphragm with piezoelectric ceramic coating according to claim 3, characterized in that, The electric field strength of the polarization electric field is 160 - 350 V / m.

9. The manufacturing method of the diaphragm with piezoelectric ceramic coating according to claim 8, characterized in that, The polarization duration is 20 - 45 minutes.

10. A diaphragm with a piezoelectric ceramic coating, characterized in that, The diaphragm is prepared by using the manufacturing method of the diaphragm with piezoelectric ceramic coating as described in any one of claims 1-9. The diaphragm includes a polymer film and piezoelectric ceramic particles laid on the surface layer of the polymer film; The polymer film is formed by laminating a cross-linked polytetrafluoroethylene film and a poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] film; The piezoelectric ceramic particles are laid on both side surfaces of the polymer film; Film through-holes are uniformly distributed on the polymer film. The thickness of the polymer film is 20-140 μm, and the aperture of the film through-holes is 20-50 μm; The piezoelectric ceramic particles are lead zirconate titanate ceramic particles, and the particle size of the piezoelectric ceramic particles is 0.5-25 μm.

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