In-situ regeneration method of waste lithium iron phosphate battery positive electrode material

Abstract

The invention provides an in-situ regeneration method of a waste lithium iron phosphate battery positive electrode material. The in-situ regeneration method comprises the following steps: disassembling and separating out positive and negative electrode mixed powder, a battery shell, a copper foil, an aluminum foil and a diaphragm by a physical method after discharging the waste lithium ion battery; adding the positive and negative electrode mixed powder into a NaOH solution for dissolution and removing the residual Al element and then placing the mixture in a hydrochloric acid solution with acertain concentration to leach Li, Fe and PO431 , filtering and removing insoluble graphite to enable the positive electrode material to be separated from the negative electrode graphite material andrecovering and regenerating the negative electrode material after purification; then adding a lithium source, an iron source or a phosphorus source according to the determined element ratio of leaching solution to make the molar ratio of Li: Fe: PO43- to be 1-1.05: 1: 1 and adding a certain amount of carbon source; and obtaining the lithium iron phosphate coated with carbon after spray pyrolysis.The disassembling mode is simplified, the lithium iron phosphate positive electrode material can be synthesized in situ, the hydrochloric acid can be recycled, the disassembling cost of the waste battery can be reduced and industrial production can be realized.

Description

technical field [0001] The invention belongs to the technical field of recycling waste lithium iron phosphate batteries, in particular to an in-situ regeneration method for positive electrode materials of waste lithium iron phosphate batteries. Background technique [0002] With the advancement of new energy product technology, especially the demand for lithium-ion batteries in the electronic market and electric vehicle market is increasing year by year. As of the end of 2017, my country has promoted more than 1.8 million new energy vehicles and assembled about 86.9GWh of power batteries. Since 2018, lithium-ion batteries will gradually enter a large-scale decommissioning period, and there are a large number of lithium-ion battery disposal problems. However, waste lithium iron phosphate lithium-ion batteries contain reusable resources, such as lithium, aluminum, copper, iron and other valuable metals and graphite and other materials. If these batteries are not handled proper...

AI Technical Summary

Problems solved by technology

One is to use manual disassembly to separate the positive and negative pole pieces, scrape off the powder, and then recover the lithium compound and iron phosphate respectively through acid leaching and pH adjustment. CN108470952A, CN108461857A, etc., in these disclosed treatment methods, the lithium iron phosphate material is not regenerated in situ, but the lithium element and the iron element are recovered separately, the consumption of acid and alkali is large, the recovery cost is high, and the treatment of the three wastes is difficult

Another method is to directly add lithium source, iron source or phosphorus source to prepare lithium iron phosphate material after calcining, such as the documents CN108550940A, CN108172922A, CN107634222A, CN107275705A, CN106976852A, etc. disclosed by the Chinese Patent Office. High requirements (requires relatively pure positive electrode powder), the uniformity of the newly prepared material particles is difficult to ensure and is prone to impurity, and the electrochemical performance of the positive electrode material cannot be guaranteed

Another method is the document CN106276842A disclosed by the Chinese Patent Office, which is an in-situ synthesis of lithium iron phosphate precursor after leaching with an organic mixed acid, but it needs to be prepared by vacuum distillation and organic solvent precipitation, and the process is complicated, energy consumption is high, and recovery costs High, difficult to achieve industrial production

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