10results about How to "High piezoelectric coefficient" patented technology

The invention discloses an MEMS loudspeaker, a manufacturing method thereof and an electronic device, and the method comprises the steps: providing a semiconductor substrate which comprises a first surface and a second surface which are opposite to each other, and sequentially forming a vibrating diaphragm layer, an insulating layer and a first electrode layer on the first surface of the semiconductor substrate; forming a lithium niobate piezoelectric layer on the first electrode layer; forming a second electrode layer on the lithium niobate piezoelectric layer; patterning the lithium niobate piezoelectric layer, the first electrode layer, the insulating layer and the diaphragm layer to form a vibration structure and a fixed end which are separated by a groove; a flexible covering layer covering the bottom and the side wall of the groove is formed, and the vibration structure is connected with the fixed end through the flexible covering layer; and etching the semiconductor substrate from the second surface of the semiconductor substrate to form a cavity. The sound pressure level of the MEMS loudspeaker can be improved by adopting lithium niobate as the piezoelectric layer, and the amplitude of the vibration structure can be improved by adopting the flexible covering layer to connect the vibration structure and the fixed end.

This application provides a high-voltage electrochemical composite hydrogel for wound skin repair and its preparation method. The high-voltage electrochemical composite hydrogel is prepared by using hydroxyethyl cellulose and acrylamide monomers as raw materials to form an interpenetrating network structure. Polyvinylidene fluoride (PVDF) and ZnO nanowires are used as piezoelectric materials, and are formed by interweaving PVDF and ZnO nanowires within the hydrogel. This high-voltage electrochemical composite hydrogel significantly improves the crystallization orientation and polarization efficiency of PVDF through mechanical stretching and polarization, resulting in an order-of-magnitude improvement in the piezoelectric properties of the composite hydrogel. Simultaneously, it retains the excellent flexibility and biocompatibility of the hydrogel, showing broad application prospects in flexible sensors, self-powered devices, and human-computer interfaces.

The present invention provides a self-assembled omnidirectional high-temperature vibration sensor array based on two-dimensional crystal piezoelectric materials, belonging to the field of vibration sensor technology, wherein each unit includes a single crystal silicon substrate; a stress layer formed on the single crystal silicon substrate; a heterojunction formed on the stress layer, the heterojunction including a gate electrode, a dielectric layer, a two-dimensional crystal piezoelectric material layer, a source electrode, a drain electrode and a nano protective layer arranged in sequence; driven by the stress layer, the heterojunction is self-assembled into a curled semicircular three-dimensional structure. A multi-layer (≥3) circular array is performed on the above structure to obtain a three-dimensional self-assembled omnidirectional piezoelectric vibration sensor array structure. The present invention also discloses a method for making a self-assembled omnidirectional high-temperature vibration sensor array based on two-dimensional crystal piezoelectric materials. The miniaturization of the omnidirectional vibration sensor is achieved through monolithic integration, and high sensitivity, wide range and high temperature resistance detection are also achieved.

This invention relates to the field of piezoelectric ceramic materials technology, and provides a sodium bismuth titanate ceramic material with a non-stoichiometric composition at the A-site, its preparation method, and its applications. The chemical formula of the sodium bismuth titanate ceramic material is Na. 0.5‑y Bi 0.5‑x TiO3, wherein 0≤x≤0.4, 0≤y≤0.4. This invention, through compositional design and control, prepares sodium bismuth titanate piezoelectric ceramics with non-chemically composed A-sites via solid-state sintering. Different A-site defects respectively improve the coercivity and piezoelectric coefficient of the sodium bismuth titanate piezoelectric ceramics. The matrix Na... 0.5 Bi 0.5 The coercive field of TiO3 ceramics is 70 kV / cm, and the piezoelectric coefficient d is... 33 A piezoelectric ceramic sample with a coercive field of 81 kV / cm at x = 0.03 and y = 0 can achieve a piezoelectric coefficient d of 95 pC / N. 33 .

The present application relates to the technical field of lithium metal battery, and especially relates to a negative electrode interface protection layer and a preparation method, a lithium metal negative electrode and a lithium metal battery. The preparation method comprises the following steps: under stirring, adding bismuth ferrite into a PVDF-HFP solution in batches, ultrasonic dispersion and mixing, obtaining a precursor solution, dropping the precursor solution on a copper foil, adopting a two-stage spin coating process to form a wet film, drying, obtaining a copper foil loaded with a composite protection layer BFO / PVDF-HFP, and carrying out high-voltage corona polarization treatment on the copper foil loaded with the composite protection layer BFO / PVDF-HFP, thereby obtaining the negative electrode interface protection layer. The negative electrode interface protection layer is more sensitive to the stress response of the lithium metal negative electrode volume strain and lithium dendrite, and generates a stronger piezoelectric field more quickly. Under the action of the electric field, the lithium ion flux is larger and more uniform, the lithium deposition is more uniform and dense, the growth of lithium dendrites is effectively inhibited, and the lithium metal is protected while the lithium deposition / peeling behavior is more effectively regulated.

The invention discloses a piezoelectric polymer and a blood pressure monitoring device based on the piezoelectric polymer, and relates to the technical field of blood pressure monitoring, the piezoelectric polymer comprises polyvinylidene fluoride, polyvinyl alcohol and N, N-dimethylacetamide according to the weight ratio of (61-71): (19-22): (400-500); the blood pressure monitoring device comprises a pressure sensor and a signal processing system, and the pressure sensor is in communication connection with the signal processing system; a sensitive material in the pressure sensor is a piezoelectric polymer; the piezoelectric polymer has higher piezoelectric property and has higher sensitivity to the real-time change state of the blood pressure in the blood pressure monitoring process, the detection result can be more accurate, and the device is suitable for being used in the treatment process of critical patients.

This invention provides a 1D / 2D dual piezoelectric photocatalytic composite material, its preparation method, and its application, relating to the field of wastewater treatment technology. The 1D / 2D dual piezoelectric photocatalytic composite material of this invention comprises a heterojunction structure consisting of one-dimensional rod-shaped barium titanate and a two-dimensional bismuth-rich halide oxide; the one-dimensional rod-shaped barium titanate is rod-shaped BaTiO3 grown along the c-axis orientation; the two-dimensional bismuth-rich halide oxide is Bi... x O y X z X is at least one of Cl, Br, or I; the BaTiO3 and Bi x O y X z The molar ratio is (1-10):(1-10); the lattice matching degree of the heterojunction is >90%. This invention constructs a 1D / 2D dual piezoelectric heterojunction structure with high lattice matching degree, combined with a curing method involving chemical bonding of a hydroxylated modified layer and a silane coupling agent, and uses an aeration-driven approach to achieve synergistic enhancement of piezoelectric effect and photocatalytic performance. This significantly improves carrier separation efficiency and catalyst stability, reduces energy consumption, and provides a new direction for the efficient treatment of organic wastewater, showing promising application prospects.

This invention discloses a core-shell composite piezoelectric fiber material and its preparation method. The invention first prepares a core-shell composite nanofiber with PVDF-TrFE as the shell and PC as the core using a coaxial spinning process. Using PC as the core increases the elastic modulus of the composite piezoelectric fiber, resulting in a larger piezoelectric potential than pure PVDF-TrFE fibers under the same strain. Simultaneously, PC forms hydrogen bonds at the interface with PVDF-TrFE, increasing the crystallinity of the PVDF-TrFE shell and thus improving the piezoelectric properties. The core-shell composite piezoelectric fiber has a d... 33 The piezoelectric coefficient can reach 49.1 pC N. ‑1 It is 110% higher than that of pure PVDF-TrFE.

This invention discloses a barium titanate-based piezoelectric ceramic with high temperature stability and its preparation method. The ceramic has the following characteristics: Ba 1‑x Ca x Ti 1‑y Zr y O3, 0.17≤x≤0.19, 0.11≤y≤0.13. The ceramic uses BaTiO3 as the basic research system. By replacing some barium ions with calcium ions and some titanium ions with zirconium ions, the phase transition temperature of barium titanate is adjusted, so that it maintains stable piezoelectric properties over a wider temperature range, i.e., it has high temperature stability. Furthermore, by doping with calcium and zirconium sources to change the morphology and distribution of electric domains, the piezoelectric coefficient of the ceramic is increased.

The invention discloses a piezoelectric ceramic for a piezoelectric ceramic fan and a preparation method thereof, the chemical formula of the ceramic material is m% Me2O3-(1-x-y-z) Pb (Mg1 / 3Nb2 / 3) O3-xPb (Zn1 / 2Nb2 / 3) O3-yPbTiO3-zPbZrO3, Me is any one or two of Pr, Ho, Eu, Dy, Nd, Yb, La, Sm, Y, Er and Lu, m% refers to the molar percentage of Me2O3 in (1-x-y-z) Pb (Mg1 / 3Nb2 / 3) O3-xPb (Zn1 / 2Nb2 / 3) O3-yPbTiO3-zPbZrO3, 0.05 < = x < = 0.8, 0.05 < = y < During preparation, step-by-step synthesis and two-step sintering are adopted, the component gradient and proportion can be regulated and controlled, obtained ceramic grains are fine and uniform and high in density, Me2O3 rare earth element is doped into a multiphase piezoelectric ceramic matrix, good temperature stability and high piezoelectric coefficient are obtained within the range of-60 DEG C to 120 DEG C, and d33 is not lower than 1695 pC / N. The piezoelectric ceramic fan has important application in the field of piezoelectric ceramic fans, and is expected to be widely applied in the fields of precise positioning systems, medical imaging equipment, sensors and actuators, energy collection and conversion, consumer electronics, unmanned aerial vehicles and micro aircrafts.