39 results about "Lithium tungstate" patented technology

The invention provides a ternary positive pole material with a surface layer coated with lithium tungstate and doped with W and a preparation method. A precursor is prepared by a current industrial hydroxide co-precipitation method, the method is simple and convenient, the production cost is low, and the technological condition is moderate. The preparation of the ternary positive pole material with the surface layer coated with lithium tungstate and doped with W is realized by a one-step method, that is, a tungstate source is added in the mixing process of the precursor and lithium salt, thenhigh-temperature calcination is performed and the ternary positive pole material is obtained, and the preparation method is simple. The ternary positive pole material with the surface layer coated with lithium tungstate and doped with W can solve the problems that the integral circulating property of a material is poor and the like due to the fact that the surface layer structure is unstable in the circulating process of a high-nickel ternary positive pole material; according to the ternary positive pole material with the surface layer coated with lithium tungstate and doped with W, the cooperative action of coating and doping is used for improving the electromechanical property and the structure stability of the ternary positive pole material, and the high-nickel ternary positive pole material with high properties is obtained.

Provided is a method for producing a positive electrode active material for nonaqueous electrolyte secondary batteries, including: a water-washing step of mixing, with water, Li—Ni composite oxide particles represented by the formula: Li_zNi_1-x-yCo_xM_yO₂ and composed of primary particles and secondary particles formed by aggregation of the primary particles to water-wash it, and performing solid-liquid separation to obtain a washed cake; a mixing step of mixing a W compound powder free from Li with the washed cake to obtain a W-containing mixture; and a heat treatment step of heating the W-containing mixture, the heat treatment step including: a first heat treatment step of heating the W-containing mixture to disperse W on the surface of the primary particles; and subsequently, a second heat treatment step of heating it at a higher temperature than in the first heat treatment step to form a lithium tungstate compound on the surface of the primary particles.

Provided is a positive-electrode material for nonaqueous-electrolyte secondary batteries, the positive-electrode material being capable of achieving both high capacity and high output when used for a positive electrode for nonaqueous-electrolyte secondary batteries. Also, provided is a method for manufacturing the positive-electrode material for nonaqueous-electrolyte secondary batteries, wherein a lithium metal composite oxide powder is mixed with lithium tungstate, the lithium metal composite oxide powder being represented by a general formula Li_zNi_1-x-yCo_xM_yO₂ (wherein 0.10≦x≦0.35, 0≦y≦0.35, 0.97≦z≦1.20, and M is an addition element and at least one element selected from Mn, V, Mg, Mo, Nb, Ti, and Al) and comprising primary particles and secondary particles composed of aggregation of the primary particles.

The invention discloses a lithium tungstate-coated Ni-Co lithium aluminate composite material and a preparation method and an application thereof. According to the invention, a nickel-cobalt-aluminumprecursor is dispersed in a lithium-containing solution, cobalt trioxide is added, the lithium-containing solution and cobalt trioxide are subjected to a reaction to generate Li2WO4, during an evaporative crystallization process, Li2WO4 is subjected to direct deposition coating on the nickel-cobalt-aluminum precursor, and lithium-mixing sintering is carried out to obtain LiNi0.8Co0.15Al0.05O2 coated Li2WO4, and through the in-situ reaction, the formed deposited coating can form an uniform coating layer. through crystallization and deposited coating, the obtained coating layer has the advantages of good crystallinity and uniform component, and can be used in a lithium ion battery as a ternary cathode material, the circularity of the obtained lithium ion battery is stable, and the multiplying power performance is excellent.

The invention belongs to the technical field of battery materials, and discloses a cobalt-free layered nickel-manganese positive electrode material and a preparation method and application thereof. The chemical formula of the cobalt-free layered nickel-manganese positive electrode material is LiaNixMnyMezO2@Mb, wherein Me is at least one of Zr, Al, W, Sr, Ti or Mg; and M is at least one of Al2O3, CeO2, TiO2, Yb2O3, Nb2O5, La2O3, WO3, titanium sol, aluminum sol, titanium aluminum sol, aluminum isopropoxide, butyl titanate, dialuminum hydrogen phosphate or lithium tungstate. Shallow layer coating is achieved through high-temperature sintering after metal oxide coating, and the shallow layer coating of the material is beneficial for preventing microcrack expansion caused by material structure change and internal stress change in the charging and discharging process in the circulation process of the material.

The invention provides a preparation method of lithium ion battery positive electrode composite material, which comprises the following steps of: 1) dissolving tungsten source in a solvent, and addingPVP to disperse to form a mixed solution; 2) adding high nickel anode material into the mixed solution, and heating and evaporating the solvent after constant temperature stirring; 3) drying the material obtained in the step 2) and then performing dry mixing with the lithium salt; 4) sintering the dry-mixed material under the aerobic condition to obtain the lithium tungstate-coated high-nickel anode material. The coated layer of the obtained material is good in uniformity, and the coated lithium tungstate helps to improve the electrochemical performance of the high-nickel anode material, in particular to the cycling stability in the high-temperature environment.

The invention discloses a lithium ion battery cathode material, and a preparation method thereof. The preparation method comprises following steps: S1, a granular lithium-enriched manganese-based material, and preferable with a spherical morphology, is dispersed and dissolved in a mixed solution containing a lithium salt and a tungsten oxide; S2, a solution obtained in step S1 is dried up; and S3,a mixture obtained after drying in step S2 is grinded and dispersed, and is subjected to sintering so as to obtain the lithium-enriched manganese-based ternary cathode material, wherein the surface of the lithium-enriched manganese-based ternary cathode material is provided with a R-3 space group lithium tungstate coating layer. Operation of the preparation method is simple; only a small amount of a modifying material is capable of improving the circulation conservation rate and electrochemical performance of the lithium-enriched manganese-based material obviously, and obtaining the lithium ion battery cathode material with excellent rate capability.

The invention belongs to the technical field of air conditioning refrigeration and particularly relates to a special lithium bromide solution for an adsorption refrigerator and a preparation method thereof. The special lithium bromide solution for the adsorption refrigerator comprises a corrosion inhibitor which accounts for 1 to 3.5 percent of the total mass of the lithium bromide solution. The corrosion inhibitor comprises the following raw material components in parts by mass: 15 to 35 parts of lithium molybdate, 10 to 50 parts of lithium tungstate, 1 to 5 parts of lithium dihydrogen phosphate, 4 to 15 parts of hydrobromic acid, 0.5 to 2 parts of zinc dihydrogen phosphate and 0.5 to 2 parts of manganous nitrate. The special lithium bromide solution for the adsorption refrigerator is excellent in combination of a passive film layer and an inner cavity material, has more excellent corrosion resistance and good temperature resistance and stability.

The invention relates to a neodymium-doped gadolinium barium lithium tungstate laser crystal and a preparation method and application thereof. The high-quality crystal with large size is grown by using 30-60at% Li2WO4 as a fluxing agent under the conditions that the cooling rate is 0.5-2 DEG C/day and the rotating speed is 5-30r/min. The crystal belongs to the monoclinic system and has C2/c spacegroup structure. The main absorption peak of the Nd<3+>:Li3Ba2Gd3(WO4)8 crystal is 804nm, the half-peak width is 19nm and the absorption transition cross section is 5.37*10<-20>cm<2>, and the crystalis suitable for being pumped by the AsGaAl semiconductor laser. A quite wide emission band exists in the range from 850nm-1400nm. The emission transition cross section at the emission peak of 1064nm is 12.08*10<-20>cm<2>, the fluorescence lifetime is 0.153ms, and the crystal is easy to generate and output lasers with wavelength being 1064nm.

The invention discloses a method for separating and recycling tungsten in an alkaline sodium tungstate solution with a high chlorine content. The method comprises the following steps: (1) precipitating tungsten: adjusting the pH value of an alkaline sodium tungstate solution with high chlorine content to 9-13 by hydrochloric acid, then adding enough saturated calcium chloride solution to fully carry out reactions so as to precipitate tungsten, washing the precipitate, and filtering to obtain precipitate (calcium tungstate) and a tungsten precipitation mother liquor; (2) alkali decomposition: using sodium phosphate as a leaching agent to fully decompose calcium tungstate in a sodium hydroxide solution to obtain a sodium tungstate solution; (3) ion exchange: subjecting the obtained sodium tungstate solution in the alkali decomposition step to ion exchange according to a convention ion exchange method, and after desorption, performing evaporation and crystallization to obtain high purity secondary ammonium tungstate. According to the method, in the tungsten precipitation step, the tungstate groups in the alkaline sodium tungstate solution with a high chlorine content are precipitated so as to separate the tungstate groups from the chlorine ions; and then obtained calcium tungstate is decomposed by a leaching agent (sodium phosphate) under an alkaline condition so as to obtain a sodium tungstate solution, which can be applied to ion exchange, so that the alkaline sodium tungstate solution with a high chlorine content can be processed by an ion exchanged method to recycle tungsten to obtain a high purity secondary ammonium tungstate product.

The invention discloses a chromium-doped lithium tungstate magnesium crystal as well as a preparation method and an application thereof. The molecular formula of the crystal is Cr3+:Li2Mg2(WO4)3, the crystal belongs to an orthorhombic crystal system and a Pnma space group, and the cell parameter is as follows: Z=4. The crystal grows in a top seeded solvent growth method, the mixture of 75% Li2WO4 and 25% WO3 is used as a fluxing agent, the concentration ratio of the fluxing agent in the growth raw material is 55 to 80 percent, and the growth parameters are as follows: the cooling rate is 0.5 to 5 DEG C/day, the growth temperature is 800 to 880 DEG C, and the rotation speed is 5 to 30 turns/min. The crystal has the characteristics such as moderate mechanical performance, large transmission cross section and the like, the tunable range is 750nm to 1050nm, and the crystal is expected to become a novel tunable laser crystal and can be actually used.

Provided is a method for producing a positive electrode active material for nonaqueous electrolyte secondary batteries, the method including: a mixing step of obtaining a W-containing mixture of Li metal composite oxide particles represented by the formula: Li_zNi_1-x-yCO_xM_yO₂ and composed of primary particles and secondary particles formed by aggregation of the primary particles, 2 mass % or more of water with respect to the oxide particles, and a W compound or a W compound and a Li compound, the W-containing mixture having a molar ratio of the total amount of Li contained in water and the solid W compound or the W compound and the Li compound of 3 to 5 with respect to the amount of W contained therein; and a heat treatment step of heating the W-containing mixture to form lithium tungstate on the surface of the primary particles of the Li metal composite oxide particles.

The invention discloses a molybdenum removal technology for calcium tungstate production process. The molybdenum removal technology comprises the following steps of S1, vulcanizing a calcium tungstate solution containing impurity element of molybdenum, so as to convert the impurity element of molybdenum into the corresponding thioic acid radical; S2, adding a precipitant into the vulcanized calcium tungstate solution, stirring for 0.5 to 2.5h at the temperature of 20 to 70 DEG C, and forming an organic compound precipitation together with the thioic acid salt containing the impurity element of molybdenum; S3, finally, adding an adsorbate, filtering and separating, wherein the filtering liquid is the impurity-removed calcium tungstate solution, and the filtering residues are the adsorbate and the organic precipitation; S4, increasing the acidity of the calcium tungstate solution to 140 to 160g/L, and adding tungsten powder into the solution; S5, repeating the steps S1 to S4 once. The molybdenum content of the existing calcium tungstate is 2% to 3.5%. The molybdenum removal technology has the advantages that the existing smelting impurity removal procedure is improved, so that the molybdenum content of the calcium tungstate is less than 0.5%; the impurity removal effect is good, the equipment is simple, the production cost is low, the process flow is short, and the operation is easy.