Method of recycling lithium battery cathode material lithium iron phosphate

Abstract

The invention discloses a method of recycling lithium battery cathode material lithium iron phosphate. The method includes the steps of allowing a waste lithium iron phosphate battery to discharge, disassembling the waste lithium iron phosphate battery to obtain a cathode, crushing the cathode, and screening; adding the crushed and screened particles into an acid liquid for soaking so that metals,such as lithium and iron, in the particles are present in a solution in ion form; soaking, and filtering to obtain solution a; adding immobilized residue into an acid solution for soaking, stirring,and filtering to obtain solution b; adding an alkaline liquid, and stirring until no solid separates out; adding an aluminum salt into the solution with the solid separated so that lithium hydroxide separates out; dissolving crude lithium hydroxide and deionized water in a mass ratio of (0.01-0.1):1, stirring well, filtering, and separating to obtain filtrate c; heating the filtrate c, concentrating, cooling, filtering, washing the separated precipitate from filtering, and drying to obtain finished lithium hydroxide. The method herein allows lithium sources to be maximally recycled when applied to the recycle of lithium battery cathode materials.

Description

Technical field [0001] The invention relates to the field of battery materials, in particular to a method for recovering lithium iron phosphate as a positive electrode material of a lithium battery. Background technique [0002] Due to the excellent comprehensive performance of lithium-ion batteries, they have shown broad development space in portable energy storage tools, especially in the new energy automobile industry. Nowadays, the development of new energy vehicles has been raised to an unprecedented height by various countries, and the power battery as a core component has naturally received extensive research and attention. Olivine-type lithium iron phosphate, as a new generation of lithium-ion battery cathode material, has the advantages of low synthetic raw material price, high specific energy, good thermal stability, and no pollution to the environment. It shows a good market prospect in power batteries. At present, both foreign and domestic research enthusiasm for LiF...

AI Technical Summary

Problems solved by technology

However, the classic synthetic route in the liquid phase method is to use ferrous salt, phosphoric acid and lithium hydroxide as raw materials. During this reaction, the loss of lithium salt is large, and the utilization rate is only about 33.3% (take ferrous sulfate as an example below). Part of the lithium remains in the solution after the reaction. If the lithium is not recycled, the cost of lithium raw materials will inevitably increase, the waste of lithium is serious, and the environmental pollution is also very serious.