58results about How to "No obvious reunion" patented technology

The invention provides a solid phase-hydrothermal preparation method for lithium vanadium phosphate. The method comprises the following process steps that (1) providing materials of vanadium, phosphate radicals and carbon are metered according to a mol ratio of vanadium: phosphate radicals: carbon being 1:1:(1-10), dispersing agents are added for ball milling, obtained paste is dried and is then crushed, the materials are heated to 650 to 900 DEG C for heat insulation for 4 to 10 hours under the inert gas protection, the materials are naturally cooled to the room temperature along with a furnace to obtain VPO4 / C intermediates; (2) providing materials of lithium and phosphate radicals and the intermediates are metered according to a mol ratio of lithium: phosphate radicals: intermediates being 3:1:2, the providing materials of lithium and phosphate radicals are respectively prepared into water solution, water solution of the providing materials of the phosphate radicals is added into the water solution of the providing materials of lithium to form mixing solution, the intermediates are added into the mixed solution, water is added for dilution, then, the materials are transferred to a sealed high-pressure reaction kettle, are heated to 200 to 280 DEG C for heat insulation for 2 to 20 hours and are filtered, and filter cake is subjected to vacuum drying to obtain black powder; and (3) the black powder is heated to 600 to 850 DEG C for heat insulation for 1 to 10 hours under the inert gas protection, and the lithium vanadium phosphate is obtained.

The invention discloses a preparation method of nano-crystal boehmite, which comprises the following steps: (1) hydrolysis reaction: mixing distilled water and aluminum isopropoxide in a molar ratio of 50-150:1, heating to 70-90 ℃, react for 1~2h, filter the reaction product, and dry in an oven at 80-90℃ for 8-12h; (2) hydrothermal reaction, put the dried product in step (1) into a high-pressure reactor, and use distilled water as the reaction medium , the filling degree of the reactor is 60%-80%, the reaction temperature is 150-200°C, the reaction time is 4-12h, and the nano-crystal boehmite is obtained. The nano crystal boehmite product prepared by the invention has high crystallinity, regular crystal form, uniform particle size, simple dispersion condition and good dispersibility. And it has good water dispersibility, its dispersion condition is simple, the particle size distribution is uniform, and there is no obvious agglomeration phenomenon.

The invention belongs to the technical field of positive electrode materials for sodium ion batteries, and specifically discloses a preparation method of sodium vanadyl fluorophosphate positive electrode materials for sodium ion batteries. A fluorine source, a sodium source, and vanadyl phosphate are mixed to obtain a mixture, and then in a protective atmosphere, Roast at 650-900°C to get it. The preparation method of the present invention innovatively pre-converts the P source and the vanadium source in advance, and it is found that converting it into vanadyl phosphate, and then mixing it with the fluorine source and the sodium source, can unexpectedly significantly improve the electrical properties of the prepared material, In particular, the initial capacity performance and cycle stability of the material are significantly improved.