Preparation method for ferrous silicate lithium cathode material simultaneously doped with fluorine and zirconium

Abstract

The invention relates to a preparation method for a ferrous silicate lithium cathode material simultaneously doped with fluorine and zirconium, which is characterized by comprising the following steps of: weighing a lithium compound, a ferrous compound, a zirconium compound, a silicon compound and a fluorine compound as reactants in accordance with the molar ratio of lithium ion to ferrous ion to zirconium ion to silicon ion to fluorine ion being (1.90-2.05): (1-y): x: (1-z): k; weighing a carbon-containing compound or carbon powder based on 1-30 percent of total mass of the reactants; mixing the silicon compound with hot water, adding the lithium compound, then mixing all other reactants and the carbon-containing compound or the carbon powder, carrying out ball mill mixture process and vacuum drying to prepare dry powder; and placing the dry powder in an inert atmosphere or a weakly reducing atmosphere, and then preparing ferrous silicate lithium through the two-stage sintering process. The cycle performance of the prepared material is excellent in the 1C-rate current, and a good foundation can be built for industrialization.

Description

technical field

[0001] The invention belongs to the technical field of lithium-ion battery electrode materials, and relates to a preparation method of a lithium ferrous silicate cathode material that is doped with fluorine and zirconium at the same time and can be used for lithium-ion batteries, lithium batteries and supercapacitors. technical background

[0002] Lithium-ion batteries are widely used in mobile communications, notebook computers, portable electric tools, and are also the preferred power source for electric vehicles. The main factor affecting the performance and price ratio of lithium-ion batteries is the performance of its cathode materials. Since 2000, Armand et al [Patent US 6085015] have applied for a patent for the preparation of lithium ferrous silicate, Nytén et al [Nyten A, et al., Electrochem.Commun., 2005, 7 (2): 156-160.] The orthorhombic structure of lithium ferrous silicate has been reported, and the research on lithium ferrous silicate has attra...