Conductive titanium compound coated lithium iron phosphate positive electrode material and preparation method thereof

Abstract

The invention relates to a conductive titanium compound coated lithium iron phosphate positive electrode material and a preparation method thereof, and aims at providing excellent electric conductivity and lithium ion conduction property for lithium iron phosphate by adopting a conductive titanium compound as a coating. The material has a core-shell structure, a surface layer is the conductive titanium compound, and a core layer is lithium iron phosphate. The preparation method comprises the steps of (1) adding lithium iron phosphate and a titanium source into anhydrous ethanol, performing hydrolysis and spray drying, roasting the obtained powder under the protection of inert gas and cooling in a furnace; (2) adding the powder obtained in step (1) and a reducer into anhydrous ethanol, performing ultrasonic dispersion, drying, roasting under the protection of inert gas and cooling in the furnace; and (3) taking out the powder in a crucible, washing the powder with anhydrous ethanol and deionized water respectively, and finally, drying in a vacuum furnace to obtain a final product. By adopting the method, the particle size distribution of coated lithium iron phosphate is uniform, the coating has good electric conductivity and does not hinder the conduction of lithium ions, and the electrochemical performance of lithium iron phosphate can be effectively improved.

Description

technical field [0001] The invention relates to the surface coating modification of lithium iron phosphate by using a conductive titanium compound, and belongs to the field of new materials. Background technique [0002] With the development of lithium-ion battery technology, secondary lithium batteries have been widely used in electronic products, electric vehicles, hybrid vehicles, large power grids and new energy storage devices and other fields. Compared with other lithium battery cathode materials, lithium iron phosphate has high safety performance, long cycle life, high specific capacity, good stability, abundant resources, low price, non-toxic and environmental protection, etc., and is widely regarded as the most promising One of the cathode materials for lithium batteries. In addition, lithium iron phosphate has good high-temperature cycle performance and does not explode. Lithium iron phosphate is also an excellent cathode material for large-scale lithium-ion batt...

AI Technical Summary

Problems solved by technology

For example, when the carbon content is low, a complete and uniform coating layer cannot be formed on the surface of lithium iron phosphate, and sufficient electrical conductivity cannot be obtained; as the carbon content increases, the coating layer becomes thicker, which not only reduces the tap density of the active material And hinder the diffusion channel of lithium ions