Method for preparing iron phosphate material and lithium iron phosphate material by coprecipitation process

Abstract

The invention relates to the technical field of energy materials, and especially relates to a method for preparing an iron phosphate material and a lithium iron phosphate material by a coprecipitationprocess. The method comprises the following steps: S1) mixing an iron source with a phosphorus source according to a molar ratio of Fe<2+> to [PO4]<3-> of 1:1; S2) controlling the pH value to 2-4, adding an oxidizing agent, and performing 50 DEG C water bath heating and constant-temperature stirring; S3) performing suction filtration, drying and pre-calcining on a precipitate obtained in step S2)in order to obtain the iron phosphate (FePO4) material; S4) carrying out ball-milling mixing on the iron phosphate obtained in step S3 and a lithium source, adding a carbon source as a reducing agent; and S5) drying the ball-milled material obtained in step S4), and sintering the dried material in an inert gas at 650 DEG C for 10 h to obtain the lithium iron phosphate (LiFePO4 ) material. The method for preparing the iron phosphate material and the lithium iron phosphate material by the coprecipitation process allows the lithium iron phosphate material with a good crystal form to be preparedby finding a suitable pH value, so the electrical conductivity and the lithium of the lithium ion diffusion coefficient of the iron phosphate material are improved.

Description

technical field [0001] The invention relates to the technical field of energy materials, in particular to a method for preparing iron phosphate and lithium iron phosphate materials by a co-precipitation method. Background technique [0002] Lithium-ion batteries are considered to be the most promising chemical power sources due to their high operating voltage, high energy density, long cycle life, low self-discharge, no memory effect, wide operating temperature range, and no pollution to the environment, and are widely used In every corner of society, including mobile phones, cameras, laptops, electric bicycles, etc., are closely related to people's lives and are inseparable. At the same time, due to energy shortages, lithium-ion batteries are expected to partially or completely replace gasoline and become energy storage devices for electric vehicles. [0003] Lithium iron phosphate (LiFePO4) material is a new type of lithium-ion battery cathode material with a theoretical ...