49results about How to "Stoichiometric ratio is accurate" patented technology

The invention discloses a bismuth scandate-lead titanate high-temperature piezoelectric ceramic material. The bismuth scandate-lead titanate high-temperature piezoelectric ceramic material comprises a matrix with the chemical formula of xBiScO3-(1-x)PbTiO3 and bismuth trioxide (Bi2O3) in an amount which is less than 0.4 percent of the total weight of the matrix. The bismuth scandate-lead titanate high-temperature piezoelectric ceramic material is prepared by adding excess Bi2O3 into raw materials of Sc2O3, Bi2O3, Pb3O4 and TiO2 in the metering ratio according to the chemical formula of xBiScO3-(1-x)PbTiO3, wherein x is 0.35 to 0.38; and the using amount of the excess Bi2O3 is 0.1 to 0.4 percent of the total weight of the raw materials of Sc2O3, Bi2O3, Pb3O4 and TiO2 in the metering ratio according to the chemical formula of xBiScO3-(1-x)PbTiO3. The bismuth scandate-lead titanate high-temperature piezoelectric ceramic material solves the problems that ceramic sintering temperature is increased and piezoelectric and dielectric properties are reduced due to deviation of a stoichiometric ratio caused by bismuth volatilization in the sintering process of BSPT ceramic, and has high Curie temperature, excellent piezoelectric property and an actual application value in high-temperature electronic equipment. The invention also discloses a preparation method for the bismuth scandate-lead titanate high-temperature piezoelectric ceramic material. In the preparation method, the piezoelectric ceramic material is prepared by synthesizing and sintering at lower temperature, so production cost is reduced, process steps are simplified, and the material has actual application value.

The invention provides an O3 type sodium ion battery cathode material and a preparation method thereof. The preparation method comprises the following steps: firstly preparing metal salt of nickel, manganese, iron, and aluminum into a precursor solution; performing spraying pyrolysis on the precursor solution to obtain powder product; and finally uniformly mixing the powder material and the sodiumsalt to perform tabletting and high-temperature sintering to obtain the O3 type sodium ion battery cathode material. The preparation method is simple in operation, high in production efficiency, large in capacity, and strong in adaptability. The manufactured cathode material is a sheet structure, the sheet diameter is 1-5 microns, the thickness is 0.5-0.1 micron, the morphology and particle sizeis uniform, the reversible specific capacity under high voltage is high, the cycling stability is good; the charging/discharging specific capacity is measured in the 2.0-4.2V voltage interval, the first discharging specific capacity is more than 148mAh.g-1, and the coulombic efficiency is more than 92%.

The invention relates to a preparation method of a hollow tubular lithium-rich manganese-based positive electrode material. The preparation method includes the steps of (1), dissolving high-molecularpolymer A in an organic solvent to obtain spinning solution A; (2), dissolving lithium precursor, manganese salt, nickel salt and cobalt salt respectively obtain metal salt solution, dissolving high-molecular polymer B in an organic solvent to obtain a polymer solution, mixing the metal salt solution with the polymer solution uniformly to obtain spinning solution B; (3), taking the spinning solution A as an inner axle and the spinning solution B as an external axle, performing an co-axial electrospinning process to obtain nano-fiber; (4), drying the nano-fiber, calcining the nano-fiber at different stages, and then cooling to obtain a product. Compared with the prior art, the material synthesized by the method for preparing the hollow tubular lithium-rich manganese-based positive electrodematerial through the co-axial electrospinning process has the advantages of accurate stoichiometric ratio, uniform particle dispersion and the like, and also has excellent cycle performance.

The invention belongs to the high-temperature water vapor electrolyzing hydrogen preparation field, in particular to relating a preparation method of high performance solid oxide electrolytic cell oxygen electrode material. The method uses metal nitrate with the weight ratio of 5wt% to 30wt%, citric acid with the weight ratio of 1wt% to 10wt%, ammonium nitrate with the ratio percentage of 1wt% to 10wt%, ammonia with the weight ratio of 5wt% to 20wt% and deionized water with the weight ratio of 50wt% to 80wt% as raw material, and adopts a low-temperature self-propagating method to effectively prepare the powder. Firstly a plurality of metal nitrate solutions needed by the special oxygen electrode material are demarcated and prepared according to stoichiometric ratio, and after the metal nitrate solutions are mixed and stirred uniformly, incendiary agent citric acid and combustion improver ammonium nitrate are added, and ph value of the solutions is adjusted to the range of 7 to 9 by using the ammonia, and the mixed solution is evaporated till the solution changes into jelly, and then the jelly is heated continuously till the low-temperature self-propagating combustion is initiated to gain a first powder, then the first powder is processed heat treatment again to gain the aim powder. The method has the advantages of low operation temperature, high product ratio surface area, uniformed granularity, small average particle size, good sintering temperature activity, exact stoichiometric ratio and so on.

The invention discloses a preparation method of a composite conductive agent coated monocrystal-like lithium-rich manganese-based positive electrode material. The preparation method comprises the following steps: (1) regulating the Zeta potential of a multi-component composite conductive agent solution, so that the charge of the multi-component composite conductive agent solution is opposite to the charge of the monocrystal-like lithium-rich manganese-based positive electrode material solution, wherein the multi-component composite conductive agent solution is a mixed solution of graphene, carbon nanotubes and conductive carbon black; and (2) carrying out ultrasonic dispersion on the multi-component composite conductive agent solution, and then carrying out stirring dispersion, filtering,washing, drying and sintering on the multi-component composite conductive agent solution and the monocrystal-like lithium-rich manganese-based positive electrode material solution to obtain the composite conductive agent-coated monocrystal-like lithium-rich manganese-based positive electrode material. According to the invention, matrix materiasl and the graphene sheets, and the carbon nanotubes and the conductive carbon black are intertwined to form a 'point-line-surface' three-dimensional porous network structure, so that the capacity, the cycle performance and the rate capability of the material are remarkably improved.

The invention relates to a preparation method of a trace Mo-doped lamellar lithium-enriched ternary positive electrode material. The molecular formula of the prepared ternary positive electrode material is Li1.2(Mn0.54Ni0.13Co0.13)(1-x)MoxO2 (x is more than 0 and smaller than 1). The adopted preparation method is an organic co-precipitation method and comprises the steps of stirring an organic precipitator in a water bath with constant temperature, and dissolving the organic precipitator into an organic solvent so as to obtain a solution A; then dissolving soluble cobalt salt, nickel salt, manganese salt, molybdenum salt and lithium salt into deionized water to obtain a solution B; after thorough dissolution, dropwise adding the solution B into the solution A at a constant speed, reacting and drying, increasing the temperature of the obtained solid powder in a high-temperature tube furnace system, and calcining so as to obtain the trace Mo-doped lamellar lithium-enriched ternary positive electrode material. The material has uniform particles and regular polygonal morphology feature, and has relatively good electrochemical performance, the preparation process is relatively simple, and the ternary positive electrode material is suitable for industrialized scale production.

A copper-zinc-tin-sulfur micro/nano-fiber material and a method for preparing the copper-zinc-tin-sulfur micro/nano-fiber material belong to the technical field of the electronic functional material. The micro/nano-fiber material contains four elements Cu, Zn, Sn and S, has the diameter ranging from 300 to 800 nanometers, and has a zinc stannite crystal structure, wherein the mol ratio of the four elements of Cu: Zn: Sn: S is 2: 1: 1: 4. During preparation, inorganic salts of Cu, Zn and Sn and PVP (Polyvinyl Pyrrolidone) are used as the raw materials, firstly, spinning precursor solution, then spraying the spinning precursor solution to a substrate to form precursor fibers through a high-voltage electrospinning process, and finally, obtaining the targe product through certain thermal treatment and vulcanization treatment. The method provided by the invention is simple in preparation equipment, low in cost, simple and convenient to operate, and the process is easy to control; and the target product prepared has accurate stoichiometric ratio, excellent crystal habit and single phase structure, thereby having potential application in the field of efficient solar photovoltaic cells.

The invention belongs to the technical field of optical materials, and particularly discloses a preparation method of rare-earth-doped strontium fluorophosphate nanoparticles. The preparation method comprises the following steps of: firstly, mixing a rare earth compound with a strontium salt aqueous solution and uniformly stirring; secondly, adding an aqueous solution of monohydric phosphate and fluoride, adjusting the pH value of the solution to 3 and reacting for 1 hour, thirdly, adjusting the pH value of the solution to 7, reacting for 1 hour and circulating 5-10 times; reacting for multiple hours in a polytetrafluoroethylene-lined stainless steel reaction kettle by undergoing a normal temperature reaction or adopting a hydrothermal synthesis method at the controlled temperature of between 100 DEG C and 200 DEG C; and lastly, separating, washing, and drying in vacuum to obtain the rare-earth-doped strontium fluorophosphate nanoparticles. The method has the characteristics of simple preparation processes, practicability, low cost, wide applicability and application prospect and the like, and meanwhile, is beneficial to overcoming of the defect of high content of hydroxyl on the surface of a nanometer material in a preparing process and prolonging of the fluorescent lifetime of a rare-earth-doped nanometer material.

The invention relates to a lithium rich manganese based layered lithium battery cathode material, the formula is Li[Li<1-x-y-z>NixCoyMn2]O2, wherein x is more than zero and less than 0.5, y is more than zero and less than 0.5, z is more than 0.1 and less than 0.7, (1-x-y-z) is more than zero and less than 0.5, D50 is 10 to 20 micrometers, the specific surface area is 1-4 square meters per gram, and the discharging capacity reaches 200 to 300mAh per gram at charging/discharging current density of 12.5mA per gram. The preparation method comprises the following steps of: firstly, preparing a lithium source, a nickel source, a cobalt source and a manganese source; secondly, mixing original materials according to proportion to prepare a mixed salt solution; thirdly, adding polyacrylic acid and citric acid and uniformly mixing; fourthly, heating to form a stable sol, evaporating water to form gel, and drying the gel to form xerogel; and finally, sintering to obtain the lithium rich manganese based layered lithium battery cathode material. The cathode material disclosed by the invention has the advantages of high specific discharging capacity, good safety, low production cost and high performance cost rate.

A large area manufacturing method for zinc oxide nano micro generators comprises depositing a gold electrode on a substrate; coating photoresist in a spinning mode to form into a photoresist nano micro wire structure in the Y direction; etching gold electrode materials which are free of photoresist protection through ion beam etching, depositing hard mask material, namely aluminum oxide and etching aluminum oxide materials on the lateral wall to enable the photoresist to be exposed; stripping the photoresist and aluminum oxide on the photoresist through acetone and depositing a zinc oxide film through a sol-gel method; performing photoresist stripping through the ion beam etching and the acetone to form into zinc oxide nano wires; coating photoresist in a spinning mode and exposing the zinc oxide nano wires at two ends after exposure and forming; depositing a platinum electrode through electron beam evaporation, stripping the photoresist through the acetone and etching the aluminum oxide to form into a piezoelectric nano generator structure; exposing the piezoelectric nano generator to a vibration source to generate piezoelectric conversion and nano micro piezoelectric power generation. The large area manufacturing method for the zinc oxide nano micro generators achieves large area controllable production and manufacture of the low cost high mechanical energy to electric energy conversion nano generators.

The invention discloses a preparation method of a sharpened monocrystal high-voltage spinel lithium nickel manganese oxide cathode material. The preparation method comprises the steps that (1) a lithium source, a nickel source, a manganese source, dopants, a fluxing agent and organic acid are mixed evenly; (2) a heating furnace is heated up to 80-300 DEG C and subjected to heat preservation, thena mixed material obtained in the step (1) is put into the heating furnace to be subjected to heat preservation for 0.5-30 h at the temperature, and a low-temperature eutectic mixture is formed; and (3) the low-temperature eutectic mixture obtained in the step (2) is placed into the heating furnace at the preset temperature of 300-700 DEG C to be heated and ignited, then sintered and naturally cooled with the furnace, and thus the sharpened monocrystal high-voltage spinel lithium nickel manganese oxide cathode material is obtained. The preparation method is simple in process, high in efficiencyand low in equipment requirement, the raw material mixing level of a liquid phase combustion method can be reached, raw material splashing in the liquid phase combustion method ignition process is further avoided, and large-scale production is easy to realize.

The invention discloses a method for preparing YAG (yttrium aluminum garnet) nano-powder through a stearate melting method and belongs to the technical field of materials. The method comprises the following steps: (1) mixing a stearic acid ethanol solution and a yttrium nitrate solution to prepare a yttrium-stearic acid mixed solution; (2) heating the yttrium-stearic acid mixed solution and dropwise adding ammonia water, insulating the heat and preparing yttrium stearate emulsion; (3) performing centrifugal separation, washing a solid phase, drying and preparing yttrium stearate powder; (4) mixing the stearic acid ethanol solution and an aluminum nitrate solution to prepare an aluminum-stearic acid mixed solution; (5) heating the aluminum-stearic acid mixed solution, dropwisde ammonia water, insulating the heat and preparing aluminum tristearate emulsion; (6) performing centrifugal separation, washing a solid phase, drying and preparing aluminum tristearate powder; (7) mixing the two powders, heating into a molten state, uniformly stirring, thus obtaining a solid precursor; and (8) calcining to prepare the YAG nano-powder. The prepared YAG nano-powder is high in purity, uniform in particles and high in dispersibility and is suitable for preparing fluorescent powder and laser transparent ceramics. The method has the advantages of low reaction temperature, simplicity in popularization and the like and hardly causes environmental pollution.

The invention belongs to the technical field of negative-temperature-coefficient thermistors and particularly relates to an in-situ-generated layered composite negative-temperature-coefficient thermal-sensitive ceramic material, a preparation method and application. The thermal-sensitive ceramic material structurally comprises a base layer, a transition layer and a sensitive layer in sequence. Thecomposition of the base layer is a perovskite phase or a doped perovskite phase, the composition of the sensitive layer is a spinel phase or a doped spinel phase, and the composition of the transition layer is a mixture formed by mixing the perovskite phase or the doped perovskite phase with the spinel phase or the doped spinel phase in an isopyknic mode. A cold spraying technology is introducedinto preparation of layered-structure composite thermal-sensitive ceramics, the in-situ-generated layered composite negative-temperature-coefficient thermal-sensitive ceramic material is prepared, thedefect of a traditional method is overcome, the thickness of the sensitive layer and the microstructure of the material are effectively regulated and controlled, and the material has important significance on preparation of low-resistance-value, high-B-value and high-stability NTC thermal-sensitive ceramic materials for inhibiting the surge current.