38results about How to "Fast charge and discharge rate" patented technology

The invention discloses a method for preparing graphene from raw graphite ores through electrolysis. The method comprises the steps of crushing raw microcrystal graphite ores, sieving, and recycling raw materials which are not insufficiently crushed; preparing an electrode from raw microcrystal graphite ore powder or insufficiently-delaminated raw ores; electrolyzing the prepared electrode in an electrolytic tank, carrying out solid-liquid separation, and further delaminating a solid obtained by separation to obtain the insufficiently-delaminated raw ores and coarsely-prepared graphene; and separating and extracting graphene from the coarsely-prepared graphene. The method has the advantages of low cost, simple preparation process and device, simplicity in operation, good product quality, high process safety and large-scale production.

The invention relates to a preparation method of a praseodymium cobalt phosphorous-doped lithium manganese silicate composite positive material. The chemical formula of the praseodymium cobalt phosphorous-doped lithium manganese silicate is as follows: LiMn<1-x-y>CoxPrySi<1-z>PzO4, wherein x is 0.2 to 0.25, y is 0.01 to 0.02, and z is 0.22 to 0.34. The method comprises the following steps of (1) preparing a praseodymium cobalt phosphorous-doped lithium manganese silicate precursor; (2) thermally treating the praseodymium cobalt phosphorous-doped lithium manganese silicate precursor and crushing the praseodymium cobalt phosphorous-doped lithium manganese silicate precursor to obtain the precursor powder, dispersing carbon black and active carbon into acetone to form conductive carbon dispersion liquid, mixing the precursor powder and the conductive carbon dispersion liquid, and ball milling the mixture; and (3) drying, placing the mixture with 1:1 (mol)CO / CO2 into a purging intermittent converter, sintering the mixture, and grinding and filtering the mixture to obtain a product. According to the prepared praseodymium cobalt phosphorous-doped lithium manganese silicate composite positive material, the rare earth element Pr and the metal element Co are doped in the lithium manganese silicate so as to modify Mn, and partial Si elements are substituted by the P element, so that the electron conductivity and substance activity can be improved.

The invention relates to a preparation method of a multi-element doped lithium iron phosphate composite positive pole material. The chemical formula of the multi-element doped lithium iron phosphate is Li1-xKxFe1-yZnyP1-zSzO4, wherein x=0.1-0.2, y=0.2-0.3, and z=0.15-0.25. The method comprises the following steps: (1) weighing lithium acetate, iron oxalate, ammonium dihydrogen phosphate, ammonium hydrogen sulfate, zinc nitrate and potassium carbonate according to the molar weights of Li, K, Fe, Zn, P and S in the chemical formula, mixing, dissolving in deionized water to form a mixed solution, and performing nitrogen gas reduction reaction to obtain a mixture; (2) performing spray drying to obtain a spherical solid; and (3) presintering, adding starch accounting for 1-2wt% of the presintering product, uniformly grinding, and performing secondary sintering to obtain the multi-element doped lithium iron phosphate composite positive pole material. According to the prepared multi-element doped lithium iron phosphate composite positive pole material for a lithium ion battery, K, Zn and S are doped to modify the lithium iron phosphate to improve the ion diffusion performance and inhibit the aggregation phenomenon; and the surface of the lithium iron phosphate is coated with a carbon layer.