A lithium cerium lanthanum titanate ceramic with high-voltage electrical properties and a preparation method thereof

Abstract

The present invention provides a lithium cerium lanthanum titanate ceramic with high-voltage electrical properties and a preparation method thereof, relating to the technical field of piezoelectric ceramic materials. The general formula of the lithium cerium lanthanum titanate ceramic of the present invention is La 2‑x (LiCe) x / 2 Ti2O7, wherein 0 < x ≤ 0.08. By doping Li / Ce doubly at the A-site in an appropriate amount, the long-range order and ferroelectric order of the crystal lattice are destroyed in the present invention. This local inhomogeneity enables the piezoelectric ceramic to maintain an ultra-high Curie temperature T C and resistivity, and at the same time, it also has high piezoelectric properties.

Description

Technical Field

[0001] The present invention relates to the technical field of piezoelectric ceramic materials, and particularly relates to a lithium cerium lanthanum titanate ceramic with high piezoelectric properties and a preparation method thereof. Background Art

[0002] Piezoelectric ceramics, as important functional ceramics that can achieve the mutual conversion of mechanical energy and electrical energy, play a crucial role in people's lives and industrial production, such as ultrasonic flow velocity measurement, medical imaging, piezoelectric generators, and geological exploration. With the rapid development of modern industry, in high-tech fields such as energy, aerospace, and national defense industries, the application of piezoelectric materials has shifted from conventional use to service in extreme environments. For example, high-power ultrasonic transducers such as ultrasonic machining and ultrasonic welding, high-temperature ultrasonic positioning detectors used in nuclear reactors, and fuel injection piezoelectric valves used in internal combustion engines must select piezoelectric materials with high Curie temperatures to ensure the normal operation of piezoelectric devices within a relatively high temperature range. Therefore, the application in high-temperature fields poses higher requirements for piezoelectric ceramic materials in terms of working temperature, resistivity, piezoelectric properties, and high-temperature stability.

[0003] Since the piezoelectric coefficient d of piezoelectric ceramics 33 is higher, its Curie temperature T C is lower, and vice versa. Therefore, the highest service temperature of piezoelectric ceramics is between 1 / 2T C and 3 / 4T C For example, the Curie temperature of bismuth-layered structure piezoelectric ceramics is about 900 °C, but its highest service temperature is about 500 °C, which cannot meet the requirements of piezoelectric devices in the ultra-high temperature region.

[0004] The Curie temperature of perovskite-like layered structure ceramic lanthanum titanate (La2Ti2O7, abbreviated as LTO) is as high as 1450 °C, and it is expected to meet the application requirements of piezoelectric devices in the ultra-high temperature region. However, the piezoelectric coefficient d of pure-phase LTO ceramics 33 is about 1.5 pC / N, which severely restricts the practical application of LTO ceramics.

[0005] The piezoelectric properties of LTO-based ceramics are affected by the substitution of certain A or B cations in the perovskite-like layered structure (A2B2O7), which in turn affects its phase transformation, grain structure, and ferroelectric domain structure. The present invention discovers that the appropriate amount of A-site Li / Ce double doping destroys the long-range order and ferroelectric order of the lattice, and this local inhomogeneity enables the piezoelectric ceramic to have high piezoelectric properties while maintaining an ultra-high Curie temperature T C and resistivity. Summary of the Invention

[0006] Based on this, the present invention provides a lithium cerium lanthanum titanate ceramic with high piezoelectric properties and a preparation method thereof. By doping Li / Ce at the A-site in an appropriate amount, the long-range order and ferroelectric order of the lattice are disrupted. This local inhomogeneity enables the piezoelectric ceramic to maintain an ultra-high Curie temperature T C and resistivity, while also having high piezoelectric properties.

[0007] The general formula of the lithium cerium lanthanum titanate ceramic with high piezoelectric properties of the present invention is as follows:

[0008] La 2-x (LiCe) x / 2 Ti2O7, where 0 < x ≤ 0.08.

[0009] Preferably, the piezoelectric properties of the lithium cerium lanthanum titanate ceramic of the present invention are as follows: the piezoelectric constant d 33 at room temperature is 2.2 - 6.4 pC / N, the piezoelectric coefficient d 33 of the ceramic after annealing at 900 °C is 2.4 - 6.7 pC / N, the Curie temperature is 1300 - 1450 °C, and the resistivity ρ at 1000 °C is 1.0×10 5 - 9.0×10 5 Ω·cm.

[0010] The preparation method of the lithium cerium lanthanum titanate ceramic with the above high piezoelectric properties of the present invention includes the following steps:

[0011] (1) Prepare the pre-sintered powder

[0012] Weigh the raw materials according to the general formula of the lithium cerium lanthanum titanate ceramic, perform ball milling on the raw materials, dry the ball-milled raw materials, and then pre-sinter at 1100 °C - 1250 °C for 4 h - 6 h to obtain the pre-sintered powder;

[0013] (2) Secondary ball milling

[0014] Perform secondary ball milling on the pre-sintered powder, where the time for secondary ball milling is 10 h - 24 h, the rotation speed is 180 r / min - 350 r / min, and dry the ball-milled raw materials to obtain the dried ceramic powder;

[0015] (3) Granulation and tabletting

[0016] Add a polyvinyl alcohol binder to the ceramic powder dried in step (2), and mix to obtain a mixed material; the mass concentration of the polyvinyl alcohol binder in the mixed material is 5 wt% - 10 wt%; granulate the mixed material to form uniformly distributed particles, and then perform pressing on the particles to obtain a ceramic wafer;

[0017] (4) Debinding and sintering

[0018] Debind the ceramic wafer at a temperature of 800°C to 1000°C, and then sinter it at a temperature of 1400°C to 1600°C for 4h to 10h to obtain a sintered ceramic wafer;

[0019] (5) Form a dense platinum electrode layer on the surface of the ceramic wafer

[0020] Coat the surface of the sintered ceramic wafer with platinum paste, and then sinter it at a temperature of 800°C to 1000°C for 10min to 30min to form a dense platinum electrode layer on the surface of the ceramic wafer;

[0021] (6) Polarization

[0022] Put the ceramic wafer processed in step (5) directly into an oil bath with silicone oil as the medium and a temperature of 120 - 220°C, and polarize it at 8kV / mm to 12kV / mm for 15min to 30min to obtain a lithium cerium lanthanum titanate ceramic with high piezoelectric properties.

[0023] Preferably, the ball milling time in step (1) is 10h to 24h, and the ball milling speed is 180r / min to 350r / min.

[0024] Preferably, in step (3), press the particles under a pressure of 10MPa to 25MPa to obtain a ceramic wafer with a diameter of 8mm to 20mm and a thickness of 0.8mm to 1.5mm.

[0025] Preferably, the concentration of the platinum paste in step (5) is 5wt% to 15wt%.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention uses appropriate A-site Li / Ce double doping to optimize the piezoelectric properties of lanthanum titanate ceramics. The best piezoelectric properties of the doped and modified ceramic material are: the piezoelectric coefficient d at room temperature 33 is 6.4pC / N, the piezoelectric coefficient d after annealing at 900°C 33 is 6.7pC / N, the Curie temperature T C is 1408°C, and the resistivity ρ at 1000°C = 8.9×10 5 Ω·cm;

[0028] 2. The appropriate A-site Li / Ce double doping in the present invention destroys the long-range order and ferroelectric order of the crystal lattice. This local inhomogeneity helps to improve the piezoelectric properties of LTO-based ceramics, enabling the ceramic material to still maintain an ultra-high Curie temperature T C and resistivity, thereby improving the comprehensive electrical properties of the ceramic material. Description of the Drawings

[0029] Figure 1X-ray diffraction patterns of the lithium cerium lanthanum titanate ceramics prepared in Examples 1 to 4 of the present invention;

[0030] Figure 2 Scanning electron microscope photos (SEM) of the lithium cerium lanthanum titanate ceramics prepared in Examples 1 and 3 of the present invention;

[0031] Figure 3 Transmission electron microscope photos (TEM) of the lithium cerium lanthanum titanate ceramics prepared in Examples 1 and 3 of the present invention;

[0032] Figure 4 PFM images of the lithium cerium lanthanum titanate ceramics prepared in Examples 1 and 3 of the present invention, with a scanning area of 4×4 μm;

[0033] Figure 5 Piezoelectric constants d of the lithium cerium lanthanum titanate ceramics prepared in Examples 1 to 4 of the present invention 33 and Curie temperature T C ;

[0034] Figure 6 d of the lithium cerium lanthanum titanate ceramics prepared in Examples 1 and 3 of the present invention was measured at room temperature after annealing at different temperatures for 30 min 33 ;

[0035] Figure 7 High-temperature dielectric temperature curves of the lithium cerium lanthanum titanate ceramics prepared in Examples 1 to 4 of the present invention;

[0036] Figure 8 Dielectric loss tanδ of the lithium cerium lanthanum titanate ceramics prepared in Examples 1 to 4 of the present invention at different temperatures;

[0037] Figure 9 Electric hysteresis loop diagrams of the lithium cerium lanthanum titanate ceramics prepared in Examples 1 to 4 of the present invention;

[0038] Figure 10 Variation curves of the resistivity of the lithium cerium lanthanum titanate ceramics prepared in Examples 1 to 4 of the present invention with temperature. Detailed implementation manners

[0039] The present invention will be specifically described below through examples. It is necessary to point out here that these examples are only used to further illustrate the present invention and should not be construed as limiting the protection scope of the present invention. Those skilled in the art can make some non-essential improvements and adjustments based on the content of the present invention above.

[0040] Example 1

[0041] (1) Preparation of pre-fired powder

[0042] Weigh La2O3 and TiO2 according to the general formula La2Ti2O7 of lanthanum cerium titanate ceramics, and place the raw materials in a polyurethane ball milling tank (where the mass ratio of the raw materials to zirconia balls is 1:2, and anhydrous ethanol is used as the dispersion medium (the mass-volume ratio of the raw materials to anhydrous ethanol is 1 g:2 mL)), and put it into a planetary ball mill for ball milling for 20 hours (the rotation speed is 300 r / min) for ball milling treatment. Dry the ball-milled slurry, where the drying temperature is 200 °C and the drying time is 2 h, and then pre-calcine at 1200 °C for 5 h to obtain a pre-calcined powder;

[0043] (2) Secondary ball milling

[0044] Place the pre-calcined powder in a polyurethane ball milling tank again (where the mass ratio of the pre-calcined powder to zirconia balls is 1:2, and anhydrous ethanol is used as the dispersion medium (the mass-volume ratio of the pre-calcined powder to anhydrous ethanol is 1 g:2 mL)), and put it into a planetary ball mill for ball milling for 24 hours (the rotation speed is 350 r / min) for secondary ball milling treatment. Dry the ball-milled slurry to obtain a dry ceramic powder;

[0045] (3) Granulation and tabletting

[0046] Add a polyvinyl alcohol binder to the ceramic powder dried in step (2), and mix to obtain a mixed material; the mass concentration of the polyvinyl alcohol binder in the mixed material is 8 wt%; granulate the mixed material to form uniformly distributed particles, and then press the particles at a pressure of 20 MPa to obtain a ceramic wafer with a diameter of 10 mm and a thickness of 1.0 mm;

[0047] (4) Debinding and sintering

[0048] Debind the ceramic wafer at a temperature of 900 °C, and then sinter at a temperature of 1500 °C for 8 h to make a sintered ceramic wafer;

[0049] (5) Form a dense platinum electrode layer on the surface of the ceramic wafer

[0050] Coat a 10% platinum paste on the surface of the sintered ceramic wafer, and then sinter at a temperature of 1000 °C for 10 min to form a dense platinum electrode layer on the surface of the ceramic wafer;

[0051] (6) Polarization

[0052] Directly place the ceramic wafer processed in step (5) into an oil bath with silicone oil as the medium and a temperature of 220 °C, and perform polarization at 10 kV / mm for 25 min to obtain lanthanum cerium titanate ceramics with high piezoelectric properties, marked as 1 # 。

[0053] Example 2

[0054] (1) Preparation of pre-sintered powder

[0055] According to the general formula La of lanthanum lithium cerium titanate ceramics 1.98 (LiCe) 0.010 Ti2O7, weigh out La2O3, TiO2, Li2CO3 and CeO2, and place the raw materials in a polyurethane ball milling tank (where the mass ratio of the raw materials to zirconium balls is 1:2, using anhydrous ethanol as the dispersion medium (the mass-volume ratio of the raw materials to anhydrous ethanol is 1 g:2 mL), put it into a planetary ball mill and ball mill for 20 hours (the rotation speed is 300 r / min) for ball milling treatment, dry the ball-milled slurry, where the drying temperature is 200 °C and the drying time is 2 h, and then pre-sinter at 1200 °C for 5 h to obtain the pre-sintered powder;

[0056] (2) Secondary ball milling

[0057] Place the pre-sintered powder again in a polyurethane ball milling tank (where the mass ratio of the pre-sintered powder to zirconium balls is 1:2, using anhydrous ethanol as the dispersion medium (the mass-volume ratio of the pre-sintered powder to anhydrous ethanol is 1 g:2 mL), put it into a planetary ball mill and ball mill for 24 hours (the rotation speed is 350 r / min) for secondary ball milling treatment, and dry the ball-milled slurry to obtain the dry ceramic powder;

[0058] (3) Granulation and tabletting

[0059] Add a polyvinyl alcohol binder to the ceramic powder dried in step (2), and obtain a mixed material after mixing; the mass concentration of the polyvinyl alcohol binder in the mixed material is 8 wt%; granulate the mixed material to form uniformly distributed particles, and then press the particles at a pressure of 20 MPa to obtain a ceramic wafer with a diameter of 10 mm and a thickness of 1.0 mm;

[0060] (4) Debinding and sintering

[0061] Debind the ceramic wafer at a temperature of 900 °C, and then sinter at a temperature of 1500 °C for 8 h to make a sintered ceramic wafer;

[0062] (5) Form a dense platinum electrode layer on the surface of the ceramic wafer

[0063] Coat a platinum paste with a mass concentration of 10% on the surface of the sintered ceramic wafer, and then sinter at a temperature of 1000 °C for 10 min to form a dense platinum electrode layer on the surface of the ceramic wafer;

[0064] (6) Polarization

[0065] The ceramic wafer after the treatment in step (5) is directly placed into an oil bath with silicone oil as the medium and a temperature of 220 °C, and polarized at 10 kV / mm for 25 min to obtain a lithium cerium lanthanum titanate ceramic with high piezoelectric properties, marked as 2 # 。

[0066] Example 3

[0067] (1) Preparation of pre-sintered powder

[0068] According to the general formula La of lithium cerium lanthanum titanate ceramic 1.97 (LiCe) 0.015 Ti2O7, weigh La2O3, TiO2, Li2CO3 and CeO2, and place the raw materials in a polyurethane ball mill (where the mass ratio of the raw materials to zirconium balls is 1:2, and anhydrous ethanol is used as the dispersion medium (the mass-volume ratio of the raw materials to anhydrous ethanol is 1 g:2 mL)), put it into a planetary ball mill and mill for 20 hours (the rotation speed is 300 r / min) for ball milling treatment, dry the milled slurry, where the drying temperature is 200 °C and the drying time is 2 h, and then pre-sinter at 1200 °C for 5 h to obtain the pre-sintered powder;

[0069] (2) Secondary ball milling

[0070] Place the pre-sintered powder again in a polyurethane ball mill (where the mass ratio of the pre-sintered powder to zirconium balls is 1:2, and anhydrous ethanol is used as the dispersion medium (the mass-volume ratio of the pre-sintered powder to anhydrous ethanol is 1 g:2 mL)), put it into a planetary ball mill and mill for 24 hours (the rotation speed is 350 r / min) for secondary ball milling treatment, and dry the milled slurry to obtain dry ceramic powder;

[0071] (3) Granulation and tabletting

[0072] Add a polyvinyl alcohol binder to the ceramic powder dried in step (2), and mix to obtain a mixed material; the mass concentration of the polyvinyl alcohol binder in the mixed material is 8 wt%; granulate the mixed material to form uniformly distributed particles, and then press the particles at a pressure of 20 MPa to obtain a ceramic wafer with a diameter of 10 mm and a thickness of 1.0 mm;

[0073] (4) Debinding and sintering

[0074] Debind the ceramic wafer at a temperature of 900 °C, and then sinter at a temperature of 1500 °C for 8 h to make a sintered ceramic wafer;

[0075] (5) Form a dense platinum electrode layer on the surface of the ceramic wafer

[0076] Coat the surface of the sintered ceramic wafer with platinum paste having a mass concentration of 10%, and then sinter at a temperature of 1000°C for 10 minutes to form a dense platinum electrode layer on the surface of the ceramic wafer;

[0077] (6) Polarization

[0078] Directly place the ceramic wafer processed in step (5) into an oil bath with silicone oil as the medium and a temperature of 220°C, and perform polarization at 10 kV / mm for 25 minutes to obtain a lithium cerium lanthanum titanate ceramic with high piezoelectric properties, labeled as 3 # 。

[0079] Example 4

[0080] (1) Preparation of pre-sintered powder

[0081] According to the general formula La of lithium cerium lanthanum titanate ceramic 1.96 (LiCe) 0.020 Ti2O7, weigh La2O3, TiO2, Li2CO3 and CeO2, and place the raw materials in a polyurethane ball mill tank (where the mass ratio of the raw materials to the zirconium balls is 1:2, and anhydrous ethanol is used as the dispersion medium (the mass-volume ratio of the raw materials to anhydrous ethanol is 1 g:2 mL)), put it into a planetary ball mill and mill for 20 hours (the rotation speed is 300 r / min) for ball milling treatment, dry the milled slurry, where the drying temperature is 200°C and the drying time is 2 h, and then pre-sinter at 1200°C for 5 h to obtain the pre-sintered powder;

[0082] (2) Secondary ball milling

[0083] Place the pre-sintered powder again in a polyurethane ball mill tank (where the mass ratio of the pre-sintered powder to the zirconium balls is 1:2, and anhydrous ethanol is used as the dispersion medium (the mass-volume ratio of the pre-sintered powder to anhydrous ethanol is 1 g:2 mL)), put it into a planetary ball mill and mill for 24 hours (the rotation speed is 350 r / min) for secondary ball milling treatment, and dry the milled slurry to obtain dry ceramic powder;

[0084] (3) Granulation and tabletting

[0085] Add polyvinyl alcohol binder to the ceramic powder dried in step (2), and mix to obtain a mixed material; the mass concentration of polyvinyl alcohol binder in the mixed material is 8 wt%; granulate the mixed material to form uniformly distributed particles, and then press the particles at a pressure of 20 MPa to obtain a ceramic wafer with a diameter of 10 mm and a thickness of 1.0 mm;

[0086] (4) Debinding and sintering

[0087] Debind the ceramic wafer at a temperature of 900°C, and then sinter at a temperature of 1500°C for 8 h to make a sintered ceramic wafer;

[0088] (5) Form a dense platinum electrode layer on the surface of the ceramic wafer

[0089] Coat the surface of the sintered ceramic wafer with platinum paste having a mass concentration of 10%, and then sinter at a temperature of 1000 °C for 10 min to form a dense platinum electrode layer on the surface of the ceramic wafer;

[0090] (6) Polarization

[0091] Directly place the ceramic wafer processed in step (5) into an oil bath with silicone oil as the medium and a temperature of 220 °C, and perform polarization at 10 kV / mm for 25 min to obtain lithium cerium lanthanum titanate ceramics with high piezoelectric properties, labeled as 4 # 。

[0092] Perform electrical property testing and characterization on the lithium cerium lanthanum titanate ceramics prepared in Examples 1-4, as Figures 1 - 10 shown. (Detection conditions: After standing in an environment of room temperature 25 °C and humidity 45-65% RH for 24 h, use relevant instruments to measure various electrical parameters (d 33 , ε r , tanδ, ρ, etc.) of the sample, where the test frequencies of the dielectric constant and loss are 1 MHz.)

[0093] Among them, the phase structure analysis of the lithium cerium lanthanum titanate ceramics was carried out by using an X-ray diffractometer (XRD, X’Pert Pro MPD, B.V.PANalytical), as detailed in Figure 1 shown. The results show that: the lithium cerium lanthanum titanate ceramics of the present invention have a single perovskite-like layered structure. A significant increase in the intensity of the (004) crystal plane was observed in the Li / Ce-doped LTO-based ceramics. This result indicates that Li / Ce has been embedded in the lattice and affects the specific phase of the crystal structure.

[0094] The surface morphology of the lithium cerium lanthanum titanate ceramics was observed by using a scanning electron microscope (SEM, Apreo S, Thermo Scientific), as detailed in Figure 2 shown. The results show that: the lithium cerium lanthanum titanate ceramics show densely packed lamellar grains, with different grain sizes and relatively dense and close arrangements.

[0095] The microstructure of the lithium cerium lanthanum titanate ceramics was observed by using a transmission electron microscope (TEM, FEI Tecnai G2 F20), as detailed in Figure 3 shown. The results show that: the doping of Li / Ce reduces the local crystal plane spacing, indicating that the doping of Li / Ce destroys the long-range order of the material structure.

[0096] The ferroelectric domain structure of lithium cerium lanthanum titanate ceramics was observed using a piezoresponse force microscope (PFM, Asylum Research), as detailed in Figure 4 shown. The results indicate that lithium cerium lanthanum titanate ceramics have strip domains on the submicron scale.

[0097] The room-temperature piezoelectric properties and annealing curve of lithium cerium lanthanum titanate ceramics were measured using a d33 piezoelectric tester (ZJ-3A), as detailed in Figure 5 and Figure 6 shown. The results show that the piezoelectric properties of lithium cerium lanthanum titanate ceramics are significantly higher than those of LTO ceramics, with the highest increase being about four times. At the same time, the piezoelectric properties of lithium cerium lanthanum titanate ceramics are also very stable at high temperatures, indicating that lithium cerium lanthanum titanate ceramics have excellent electrical stability.

[0098] The high-temperature dielectric temperature curve and dielectric loss of lithium cerium lanthanum titanate ceramics were measured using an ultra-high-temperature dielectric temperature impedance spectrometer (DMS-1650, Partulab), as detailed in Figure 7 and Figure 8 shown. The results show that as the measurement temperature increases, the temperature at which lithium cerium lanthanum titanate ceramics transform from the monoclinic phase to the orthorhombic phase increases from 780 °C to about 1000 °C, indicating that Li / Ce double doping can inhibit the structural transformation of lithium cerium lanthanum titanate ceramics to the orthorhombic phase. At the same time, lithium cerium lanthanum titanate ceramics have a high Curie temperature, all above 1400 °C. The dielectric loss of lithium cerium lanthanum titanate ceramics shows no obvious change before 1000 °C, indicating that Li / Ce double doping can effectively reduce the dielectric loss of LTO ceramics.

[0099] The ferroelectric hysteresis loop of lithium cerium lanthanum titanate ceramics was measured using a ferroelectric analyzer (aixACCT TF Analyzer 1000), as detailed in Figure 9 shown. The results show that compared with LTO ceramic materials, the leakage current of lithium cerium lanthanum titanate ceramics is significantly reduced, indicating that Li / Ce double doping effectively reduces the defects in the ceramic structure.

[0100] The resistivity of lithium cerium lanthanum titanate ceramics was measured using a high-temperature insulation resistance meter (HGDZ-1000, Huace), as detailed in Figure 10 shown. The results show that the high-temperature resistivity of lithium cerium lanthanum titanate ceramics increases significantly, especially in the range of 600 °C to 1000 °C. Compared with LTO ceramic materials, the resistivity of lithium cerium lanthanum titanate ceramics can increase by up to two orders of magnitude.

[0101] In summary, in the lithium cerium lanthanum titanate ceramics prepared by the present invention, Li / Ce doping occupies the A site, significantly affecting the microstructure, piezoelectric properties, and resistivity of piezoelectric ceramics. In addition, the local inhomogeneity caused by Li / Ce doping improves the piezoelectric properties of the ceramics, among which at 3 #Optimal piezoelectric properties can be obtained in lithium cerium lanthanum titanate ceramics: the piezoelectric constant d at room temperature 33 = 6.4 pC / N, and the piezoelectric coefficient d of the ceramic after annealing at 900 °C 33 is 6.7 pC / N, the Curie temperature T C = 1408 °C and the resistivity ρ = 8.9×10 5 Ω·cm at 1000 °C, making lithium cerium lanthanum titanate ceramics promising for a wide range of applications at high temperatures.

[0102] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A lithium cerium lanthanum titanate ceramic with high-voltage electrical properties, characterized in that, The general formula of the lithium cerium lanthanum titanate ceramic is as follows: La 2-x (LiCe) x / 2 Ti2O7, where 0 < x ≤ 0.

08.

2. The lithium cerium lanthanum titanate ceramic with high-voltage electrical properties according to claim 1, wherein The piezoelectric properties of the lithium cerium lanthanum titanate ceramics are as follows: the piezoelectric constant d at room temperature 33 is 2.2 - 6.4 pC / N, and the piezoelectric coefficient d of the ceramics after annealing at 900 °C 33 is 2.4 - 6.7 pC / N, the Curie temperature is 1300 - 1450 °C, and the resistivity ρ at 1000 °C is 1.0×10 5 - 9.0×10 5 Ω·cm.

3. The preparation method of a lithium cerium lanthanum titanate ceramic with high-voltage electrical properties according to claim 1 or 2, characterized in that, It includes the following steps: (1) Prepare the pre-sintered powder Weigh the raw materials according to the general formula of the lithium cerium lanthanum titanate ceramic, and perform ball milling on the raw materials. Dry the ball-milled raw materials, and then pre-sinter at 1100°C - 1250°C for 4h - 6h to obtain the pre-sintered powder; (2) Secondary ball milling Perform secondary ball milling on the pre-sintered powder. The time for secondary ball milling is 10h - 24h, and the rotation speed is 180r / min - 350r / min. Dry the ball-milled raw materials to obtain the dried ceramic powder; (3) Granulation and tabletting Add a polyvinyl alcohol binder to the ceramic powder dried in step (2), and mix to obtain a mixed material; the mass concentration of the polyvinyl alcohol binder in the mixed material is 5wt% - 10wt%; granulate the mixed material to form uniformly distributed particles, and then perform pressing on the particles to obtain a ceramic wafer; (4) Debinding and sintering Debind the ceramic wafer at a temperature of 800°C - 1000°C, and then sinter at a temperature of 1400°C - 1600°C for 4h - 10h to make a sintered ceramic wafer; (5) Form a dense platinum electrode layer on the surface of the ceramic wafer Coat platinum paste on the surface of the sintered ceramic wafer, and then sinter at a temperature of 800°C - 1000°C for 10min - 30min to form a dense platinum electrode layer on the surface of the ceramic wafer; (6) Polarization Place the ceramic wafer processed in step (5) in an oil bath at a temperature of 120 - 220°C, and polarize at 8kV / mm - 12kV / mm for 15min - 30min to obtain the lithium cerium lanthanum titanate ceramic with high piezoelectric performance.

4. The preparation method according to claim 3, characterized in that, The time for ball milling in step (1) is 10h - 24h, and the ball milling rotation speed is 180r / min - 350r / min.

5. The preparation method according to claim 3, characterized in that, In step (3), press the particles under a pressure of 10MPa - 25MPa to obtain a ceramic wafer with a diameter of 8mm - 20mm and a thickness of 0.8mm - 1.5mm.

6. The preparation method according to claim 3, characterized in that, The concentration of the platinum paste in step (5) is 5wt% - 15wt%.

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