156results about How to "No impurity" patented technology

The invention relates to a high-purity lithium ferrous silicate anode material coated with crystalline carbon and a preparation method thereof. In the lithium ferrous silicate anode material coated with the crystalline carbon, the particle diameter of powder is 50-350 nm, and the initial discharge capacity of the anode material at the rate of C/16 is 125.7-150.3 mAhg<-1>, the weight percent of carbon is 5-15 percent by weight; a Li2FeSiO4 precursor is prepared by using a sol-gel method which comprises the following steps of: with ascorbic acids as reductants and carbon sources, catalyzing by Fe(NO3)3 while reducing ferric ions to form crystalline graphite; and uniformly coating on surfaces of Li2FeSiO4 particles, thus, the electrical property of the Li2FeSiO4/C anode material is effectively improved. Taking a carbon coating amount of 10.1 percent by weight as an example, the synthesized powder has high purity and is free of impurity phases; the initial discharge capacity at the rate of C/16 is 150.3 mAhg<-1>; and after circulation forty times, the specific ratio is 137.2 mAhg<-1>, which embodies better rate performance and better circulation performance.

The invention specifically relates to silicon carbide powder and a preparation method thereof. According to a technical scheme, the preparation method comprises the following steps of: uniformly mixing 5-20 percent by weight of nano-silicon dioxide or silica micro-powder, 0.5-2.5 percent by weight of carbon black or amorphous graphite powder, 70-88 percent by weight of an alkali metal chloride and 5-15 percent by weight of aluminum powder serving as raw materials; putting the uniformly-mixed raw materials into a tubular electric furnace, raising the temperature to 800-1,000 DEG C at the temperature raising rate of 4-10 DEG C per minute under the atmosphere of argon, and preserving heat for 2-10 hours; and putting an obtained product into nitric acid of which the concentration is 2-5 mol/L for soaking for 3-8 hours, filtering, cleaning with deionized water till the pH value of a cleaning solution is 7.0, and drying at the temperature of 110 DEG C for 8-24 hours to obtain silicon carbide powder. The method has the characteristics of low reaction temperature, simple process, controllable synthesis process, low production cost, and the like; and the prepared silicon carbide powder has the characteristics of high crystallization, high product purity, freeness from an impure phase and powder particle size of 50-200 nanometers.

The invention discloses a method for quickly preparing an Ag2Se block thermoelectric material through self-homogenization for the first time. Ag powder and Se powder are used as raw materials; firstly the raw materials are easily mixed, and then the mixed raw materials are directly subjected to plasma activated sintering (PAS), so compact Ag2Se block thermoelectric material can be prepared in several minutes. The process dissolved by the method is super easy, the preparation time is super short, the obtained product is uniform in component distribution, and an obvious effect of self-homogenization is shown. The prepared Ag2Se block thermoelectric material is superior in performance, the room temperature ZT exceeds 0.6, and a good foundation is laid for large-scale preparation and large-scale application of the Ag2Se compound.

The invention relates to a method for in-situ synthesis of a carbon coated-hydrated V3O7 nanobelt and a lithium ion battery, and discloses a method for in-situ synthesis of the carbon coated-hydrated V3O7 nanobelt. The method comprises the following steps of respectively heating reaction raw materials to a certain temperature by a high-temperature hybrid hydrothermal method, mixing the reaction raw materials, cooling the reaction raw materials to a room temperature after completion of the hydrothermal reaction, and carrying out heat preservation and drying processing to obtain the in-situ carbon coated V3O7H2O (V3O7H2O@C) nanobelt. The in-situ synthesis of the carbon coated-hydrated V3O7H2O nanobelt with high crystallinity and high structural strength is achieved by the novel high-temperature hybrid hydrothermal method; the material obtained through preparation can be used for an electrode material of the lithium ion battery; and moreover, the carbon coated-hydrated V3O7H2O nanobelt is endowed with very excellent electrochemical performance and can be applied to the field of the lithium ion battery.

The invention discloses a preparation method of pyrochlore-type A2B2O7 transparent ceramics, relating to A2B2O7-series nano powder preparation by a sol-gel process and belonging to the field of ceramic material preparation. The preparation method comprises the following steps: at room temperature, weighing RE2O3 and ZrOCl2.8H2O or TiCl4 according to the stoichiometric proportion, dissolving the rare earth oxide in nitric acid, adding the ZrOCl2.8H2O or TiCl4 to be dissolved, adding a mixed solution containing a dispersing agent (NH4)2SO4 and PAA (polyacrylic acid), slowly and dropwisely adding into an ammonium bicarbonate solution to obtain a precursor, and drying; adding a certain amount of sintering assistant ethyl orthosilicate or silicon dioxide sol into the precursor, carrying out ball milling, drying, screening and calcining to obtain nano powder; and carrying out compression molding, isostatic cool pressing, vacuum sintering, annealing and polishing treatment to finally obtain the transparent A2B2O7-series ceramics. By adopting the self-made high-activity nano powder to prepare the transparent A2B2O7-series ceramics at low temperature, the technique is simple and feasible.

The invention discloses a method for preparing aluminum molybdate with a cationic membrane electrolysis method. An aluminum sheet is taken as an anode, an inert electrode is taken as a cathode, an aqueous solution containing a depolarizer and sodium molybdate is taken as an anolyte, an acid solution, an alkaline solution or a salt solution is taken as a catholyte, and the aqueous solution containing the depolarizer and the sodium molybdate is electrolyzed in a double-chamber electrolytic cell with a cationic membrane serving as a diaphragm with the temperature controlled to range from the room temperature to 90 DEG C in a constant-current electrolysis or constant-voltage electrolysis manner until all Na<+> ions are transferred to a cathode chamber; a product obtained in an anode chamber is washed and filtered with deionized water, an obtained filter cake is dried at the temperature of 300-400 DEG C for 1-4 h, and the aluminum molybdate which is high in purity and free of impurity phases is obtained. According to the method, the effect of cationic membrane electrolysis is used, the Na<+> ions are transferred to the cathode chamber, the effect caused by the Na<+> ions is eliminated, the reaction time is short, and the finally obtained aluminum molybdate product is high in purity and free of the impurity phases.

The invention discloses a preparation method of positive material sodium hexafluoroferrate applicable for sodium or lithium ion batteries and a clad material thereof. Sodium hexafluoroferrate sediment is prepared in a water solution by controlling the conditions of synthetic process, the sodium hexafluoroferrate material can be obtained through filtering and drying, and then the sodium hexafluoroferrate is mixed with a clad layer substance or a precursor thereof, so that the sodium hexafluoroferrate clad material is prepared through calcinations under different atmospheres. The sodium hexafluoroferrate material obtained in the invention is good in crystallization property and free of impurity phase; the particle morphology is regular, the particle size is uniform and controllable, and the mobility is good; and the sodium hexafluoroferrate and the clad material thereof are high in specific capacity and high in cycle stability. The preparation method is simple in technology, low in energy consumption, little in pollution and good in product performance, and is extremely applicable for industrial production.

The invention provides a method for preparing nickel molybdate by using a cationic membrane electrolysis process. The method comprises the steps of utilizing a nickel sheet as an anode, a noble electrode as a cathode, an aqueous solution containing a depolarizer and sodium molybdate as an anode liquor, and an acid/alkali/salt solution as a cathode liquor; in a double-compartment electrolytic cell with a cationic membrane as a diaphragm, controlling the temperature from room temperature to 90 DEG C to electrolyze the aqueous solution containing the depolarizer and the sodium molybdate in a constant-current electrolysis or constant-voltage electrolysis manner till all Na<+> ions are transferred to a cathode compartment; simultaneously cleaning and filtering products from the anode by using deionized water to obtain a filter cake, drying the filter cake, and then increasing the temperature to 500-700 DEG C under air atmosphere at the speed of 2.5-10 DEG C/min to perform high-temperature roasting on the dried filter cake for 1-5 hours; naturally cooling down the temperature of the roasted product to the room temperature, and then obtaining the nickel molybdate with high purity and no impure phase. According to the method for preparing the nickel molybdate by using the cationic membrane electrolysis process, all the Na<+> ions are transferred to the cathode compartment under the action of the cationic membrane electrolysis, so that the Na<+> influence is eliminated and the reaction time is short.

The invention relates to a method for preparing (Ba, Sr) TiO3 nano powder by virtue of a Mg<2+> doped hydrothermal method. The method comprises the following steps: taking BaTiO3 powder and SrTiO3 powder which are synthesized by a hydrothermal method, adding water, mixing fully, then adding MgCl2, and mixing uniformly to obtain a mixed solution; and pouring the mixed solution into a hydrothermal kettle, preserving the heat at 120-180 DEG C for 4-8 hours to perform hydrothermal reaction, and performing centrifugal drying on a generated precipitate to obtain Mg<2+> doped (Ba, Sr) TiO3 nano powder. According to the method provided by the invention, the BaTiO3 powder and SrTiO3 powder which are prepared by the hydrothermal method are adopted as raw materials, then a minute quantity of MgCl2 is doped into the raw materials, and then the Mg<2+> doped (Ba, Sr) TiO3 powder is prepared by using the hydrothermal method under the condition that a mineralizer is not added, so that secondary reaction is effectively avoided, and the prepared powder is high in purity and uniform and meticulous in crystal grain, reaches a nano scale, and can effectively improve the energy storage characteristic and the breakdown resistance of ceramic when used for preparing the ceramic.

The invention discloses a preparation method of NiCo2O4. The method includes: taking an ammonia water solution as the mother liquor, injecting a metal source solution and a precipitant into the motherliquor for reaction, controlling the pH value of the reaction system in the reaction process at 11.5-12.5 and the temperature at 70-90DEG C, washing and drying the obtained product to obtain a basicnickel cobalt carbonate composite precursor, wherein the metal source solution is obtained by adding a nickel salt, a cobalt salt and a surfactant into deionized water and mixing the substances evenly; and calcining the basic nickel cobalt carbonate composite precursor to obtain a powder material, i.e. NiCo2O4. The invention also discloses a structure and application of the NiCo2O4 accordingly. The NiCo2O4 prepared according to the invention has a novel structure and porous double-hemisphere structure, and when the NiCo2O4 is used as a lithium ion battery negative electrode material, a crack between the hemispheres endows the material with a large surface area, thus being beneficial to contact of the material with an electrolyte solution. In addition, the special porous double-hemisphere structure is beneficial to diffusion of lithium ions into the material, so that the rate performance and cycle performance of the material can be effectively improved.

The invention relates to a single-phase alpha-Si3N4 micropowder and a preparation method thereof. The technical scheme is as follows: the preparation method comprises the following steps: uniformly mixing 5-30 wt% of simple substance silicon powder, 15-45 wt% of solid nitrogen source and 40-80 wt% of halide powder to prepare a mixture; putting the mixture into an electric tube furnace, heating to 1000-1300 DEG C at the heating rate of 2-10 DEG C/minute in a nitrogen atmosphere, and keeping the temperature for 2-6 hours; repeatedly washing the product with deionized water until no white precipitate appears when respectively titrating with AgNO3 and Ca(NO3)2 solutions; and finally, drying at 110 DEG C for 10-24 hours to obtain the single-phase alpha-Si3N4 micropowder. The preparation method has the characteristics of low reaction temperature, low cost, simple synthesis technique, controllable process, high yield and wide industrialization prospects. The particle size of the prepared single-phase alpha-Si3N4 micropowder is 100-500nm; and the single-phase alpha-Si3N4 micropowder has the advantages of no impurity phase, high activity, small particle aggregation and uniform particle size distribution.

The invention provides a red phosphor suitable for ultraviolet light excitation, and a preparation method thereof, and belongs to the field of luminescent technology. A chemical formula of the red phosphor is (Ba9-yMny)(R2-xCex)(SiO4)6, wherein R represents two of Lu, Y and Sc or one of Lu or Y; and x and y are molar fractions, wherein x value is equal to or larger than 0.005 but smaller than or equal to 0.25; and y value is equal to or larger than 0.01 but smaller than or equal to 0.6. An oxide, a fluoride, a carbonate and a nitrate which contain Ba, Mn, R and Ce respectively and a Si oxide are used as raw materials; and the phosphor is obtained by the steps of grinding the above materials; mixing the materials uniformly; putting the mixture in a crucible; high-temperature roasting under a reducing atmosphere; and cooling naturally. The phosphor can emit red light with the wavelength ranging for 570 nm to 630 nm under effective excitation of the ultraviolet light with wavelength ranging for 300 nm to 350 nm, and can be used as a red light component in a white LED excited by the ultraviolet light.

The invention discloses a synthetic method of a high-performance one-dimensional nanostructure vanadium oxide lithium ion battery electrode material. Meta-stable-phase VO2 (B), meta-stable-phase VO2 (A) and stable-phase V3O7.H2O powder is synthesized by the utilization of a high-temperature hydrothermal mixing method, so that the repeatability and the crystallinity of powder synthesis are improved, and the surface appearance of the powder is controlled. The synthetic method disclosed by the invention is the high-temperature hydrothermal method and not only has the advantages owned by the high-temperature hydrothermal method self, but also has the advantages that the repeatability is high, an obtained product is good in crystallinity, easy in appearance control and the like, therefore, the electrochemical performance of the synthetic method can be effectively optimized; the three kinds of vanadium oxide (VO2 (B), VO2 (A) and V3O7.H2O) powder synthesized by the utilization of the high-temperature hydrothermal mixing method are simple in synthetic method, high in purity, good in crystallization, uniform and unified in appearance and have no intermediate phase; the synthetic method is very simple, effective and feasible and plays a great role in improving the application performance of the vanadium oxide electrode material.

The invention provides a method for preparing highly-pure beta-Sialon ceramic powders, which combines a carbothermal reduction nitridation process and nano-pouring technology and comprises the following specific steps: firstly, taking ordered mesoporous silicon dioxide as a main raw material, taking soluble inorganic aluminum salt as an aluminum oxide precursor, taking an organic small molecular compound as a carbon source, and preparing a compound of mesoporous carbon/silicon oxide/aluminum oxide through nanometer pouring; then performing carbothermal reduction nitridation on the compound of the mesoporous carbon/the silicon oxide/the aluminum oxide to prepare a sample; and finally, calcining the sample in air to remove residual carbon, and cooling the sample after residual carbon is removed to prepare a product. The method has the advantages that the synthesis temperature of the preparation method is relatively low, and is favorable for reducing the required energy consumption in production; and the purity of the prepared beta-Sialon ceramic powders is high, and the particle shapes are mainly in a long rod-like shape. The preparation method can be widely used in fields of space flight, metallurgy, chemical industry and the like.

The invention discloses a method for preparing silver molybdate with a cationic membrane electrolysis method. A silver sheet is taken as an anode, an inert electrode is taken as a cathode, an aqueous solution containing a depolarizer and sodium molybdate is taken as an anolyte, an acid solution, an alkaline solution or a salt solution is taken as a catholyte, and the aqueous solution containing the depolarizer and the sodium molybdate is electrolyzed in a double-chamber electrolytic cell with a cationic membrane serving as a diaphragm at the room temperature of 90 DEG C in a constant-current electrolysis or constant-voltage electrolysis manner until all Na<+> ions are transferred to a cathode chamber; a product obtained in an anode chamber is washed and filtered with deionized water, an obtained filter cake is dried at the temperature of 100-200 DEG C for 1-2 h, and the silver molybdate which is high in purity and free of impurity phases is obtained. According to the method, the effect of cationic membrane electrolysis is used, the Na<+> ions are transferred to the cathode chamber, the effect caused by the Na<+> ions is eliminated, the reaction time is short, and the finally obtained silver molybdate product is high in purity and free of the impurity phases.

The application discloses a zirconium carbide-silicon carbide composite powder material, wherein a molar ratio of components in the zirconium carbide-silicon carbide composite powder material satisfies ZrC:SiC=1:0.1-1:10; a preparation process is easy, the cost is low, and the process is easy to control; and the obtained zirconium carbide-silicon carbide composite powder material has the advantages of submicron level, uniform composition and high purity.

A method for preparing SrZr03:Ce nanometer powder with a composite coprecipitator relates to a blue fluorescent powder preparing method. Sr(NO3)2, ZrOC12 8H20 and CE(NO3)3 which are weighed according to accurate stoichiometric ratio are dissolved in alcohol-water solution to be mixed into metal salt solution with 0.01-1 ml/L concentration. Ammonia water with 0.1-1 mol/L concentration and ammonium bicarbonate with 0.1-0.5 mol/L concentration are adopted to serve as mixed precipitator, and polyacrylamide (PAM) with 0.1-5*10-3mol/L is adopted to serve as dispersing agent. The mixed precipitator and the PAM dispersing agent are added into the metal salt solution dropwise, precursor precipitate is obtained, and samples are obtained after aging, filtering, washing, grinding, screening, calcining and ball-milling. SrZr03:Ce nanometer powder obtained through the method is good in dispersity, and average primary particle size is about 50 nm. In addition, the method for preparing SrZr03:Ce nanometer powder with the composite coprecipitator is simple in preparing process, short in period, low in cost and suitable for massive production.

The invention belongs to the production field of engineering material, particularly relates to a method for preparing carbon-nitrogen co-doped tricobalt tetroxide by vacuum calcination of a metal organic complex precursor, wherein a metal organic framework material Co-BTC is synthesized as a precursor by hydrothermal method; and a target product carbon-nitrogen co-doped tricobalt tetroxide is obtained by the high temperature treatment of the precursor under vacuum conditions. The preparation method of the precursor includes the following steps that organic ligands, cobalt salts and alkaline regulators are dispersed in aqueous solution, placed in a reactor after being magnetically stirred, then cooled by heating and insulation treatment, and the precursor is obtained after being filtered out, washed and dried. The target product has the characteristics of controllable doping amount, uniform morphology, high product purity, strong microwave absorption and adsorption performance of organic dyes.

The invention discloses novel crystal form multi-metal molybdate micro-nano-particles. The molecular formula of the novel crystal form multi-metal molybdate micro-nano-particles is Na2Zn5(MoO4)6. The invention also provides a preparing method of the novel crystal form multi-metal molybdate micro-nano-particles. According to the method, a zinc sheet is taken as an anode plate, a noble electrode is taken as the cathode, sodium molybdate aqueous solution is taken as anode liquor, hydrochloric acid is taken as catholyte, and ultrasonic electrolysis is conducted on the sodium molybdate aqueous solution with the constant-current-density electrolysis method in a double-chamber electrolytic cell with a positive ion film as the partition film; after electrolysis, products obtained in an anode chamber are cleaned and filtered with deionized water, dried, calcinated and cooled naturally in sequence to obtain pure Na2Zn5(MoO4)6 crystals. Most Na+ ions are transferred into a cathode chamber by means of the positive ion film, ions in the solution move at a higher speed under ultrasonic electrolysis, effective collision frequency of ions during crystal formation is increased, and pure Na2Zn5(MoO4)6 crystals with different shapes can be obtained.

The invention provides a method for preparing zinc tungstate by using a cationic membrane electrolysis process. The method comprises the steps of utilizing a zinc sheet as an anode, a noble electrode as a cathode, an aqueous solution containing sodium tungstate as an anode liquor, and an acid/alkali/salt solution as a cathode liquor; in a double-compartment electrolytic cell with a cationic membrane as a diaphragm, controlling the temperature from room temperature to 90 DEG C to electrolyze the aqueous solution containing sodium tungstate in a constant-current electrolysis or constant-voltage electrolysis manner till all Na<+> ions are transferred to a cathode compartment; simultaneously cleaning and filtering products from the anode by using deionized water to obtain a filter cake, drying the filter cake, and then increasing the temperature to 450-600 DEG C under air atmosphere at the speed of 2.5-10 DEG C/min to perform high-temperature roasting on the dried filter cake for 1-5 hours; naturally cooling the roasted product to the room temperature, and then obtaining the zinc tungstate with high purity and no impure phase. According to the method for preparing the zinc tungstate by using the cationic membrane electrolysis process, all the Na<+> ions are transferred to the cathode compartment under the action of the cationic membrane electrolysis, so that the Na<+> influence is eliminated and the reaction time is short.

The invention relates to a treatment method for a Ni-Co-Mn ternary waste lithium battery, which can recover high-purity lithium carbonate powder and Ni-Co-Mn ternary precursor from Ni-Co-Mn ternary waste lithium battery, achieves high purity and no impurity phase, and improves economic value of power battery recovery.

The invention provides a method for preparing ZrB2-Cu composite powder, belongs to the field of ceramic/metal composite material preparation and in particular relates to the method for preparing the ZrB2-Cu composite powder having a good internal metal-ceramic binding property. The method comprises two steps of ZrB2 preprocessing and chemical copper plating; the ZrB2 powder is chemically copper-plated by use of a chemical plating method, and then the Cu-coated ZrB2 powder can be prepared. The composite powder prepared by use of the method is good in dispersity; the copper coating is excellent in crystallinity without impurity phase; the surface of the coating is accumulated randomly by fine metal spherical particles; the coating is compact, uniform, flat and smooth, and has wide application prospect.

The invention provides a method for modifying lithium nickel manganate by replacing Mn with doped P non-equivalently. A non-metal element P is adopted to replace a small amount of Mn non-equivalentlyto realize doping modification of LiNi<0.5>Mn<1.5>O<4>; and by introducing a small amount of vacancy to the 16d position to adjust content of oxygen vacancy in the material, the ratio of ordered and disordered spinel structures in the material can be optimized. In the preparation process, citric acid is dissolved into a proper amount of deionized water firstly; next, a lithium source, a manganesesource, a nickel source and a phosphorus source are added in sequence to obtain a mixed solution; and heating and stirring are performed until the mixed solution is dried through evaporation, and next, pre-decomposition and thermal treatment are performed to obtain the P non-equivalently doped lithium nickel manganate. The P non-equivalently doped and modified lithium nickel manganate prepared bythe invention is high in tap density and purity, free of impurity phase, and quite high in rate capability and cycle performance; the capacity retention ratio is about 93% at 10C rate after 1,000 cycles; and the capacity retention ratio still can be as high as 87% after 1,600 cycles.