Synthesis method for preparing high-cost-performance lithium iron phosphate precursor by controlling crystallization

Abstract

The invention discloses a synthesis method for preparing a high-cost-performance lithium iron phosphate precursor by controlling crystallization, and relates to the technical field of battery materials, and the synthesis method comprises the following steps: S1) preparing a mixed solution of lithium salt, ferrous salt and phosphate, wherein the pH value of the mixed solution is less than 4; s2) stirring the mixed solution obtained in the step S1) at room temperature, slowly adding alkali to adjust the pH value to 6-7, heating and pressurizing the solution to a set temperature and a set pressure, and carrying out heat and pressure preservation reaction for 1-6 hours; s3) filtering the liquid to obtain a solid precipitate, and washing and drying the liquid to obtain a lithium iron phosphate precursor, wherein the set temperature ranges from 80 DEG C to 120 DEG C and the set pressure ranges from normal pressure to 0.3 MPa. The synthesis method of the lithium iron phosphate precursor disclosed by the invention is simple and rapid, the reaction conditions are easy to control, and the method is convenient to popularize and apply and beneficial to industrial implementation.

Description

technical field [0001] The invention relates to the technical field of battery materials, in particular to a synthesis method for preparing a cost-effective lithium iron phosphate precursor by controlling crystallization. Background technique [0002] In 1997, Padhi et al. obtained LiFePO with a regular olivine structure. 4 , its theoretical capacity is as high as 170mAh / g, excellent charge-discharge cycle performance, low price, excellent high-temperature performance, environment-friendly and pollution-free, so LiFePO 4 It is considered to be a very ideal cathode material for ion batteries. At present, the production technology of lithium iron phosphate can be generally divided into two types: solid-phase method and liquid-phase method. The solid-phase method is currently the most widely used and most mature method for synthesizing lithium iron phosphate. The iron source used in the solid-phase synthesis method is generally iron oxide, iron phosphate, etc., the lithium so...

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Problems solved by technology

[0003] The purpose of this application is to overcome the problems in the prior art that the preparation of lithium iron phosphate by the liquid phase method has high requirements on the control of production conditions and is difficult to industrialize, and to provide a synthesis method for the preparation of cost-effective lithium iron phosphate precursor with simple production process and controlled crystallization

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