Wet repair and regeneration method for waste lithium iron phosphate positive electrode material

Abstract

The invention discloses a wet repair and regeneration method for a waste lithium iron phosphate positive electrode material, which comprises the following steps: S1, soaking a waste lithium iron phosphate positive electrode plate by using an organic solvent, and drying to obtain a clean lithium iron phosphate positive electrode plate; s2, soaking the clean lithium iron phosphate positive plate in N-methyl pyrrolidone, performing ultrasonic treatment, and performing solid-liquid separation to obtain LFP powder and an aluminum sheet; s3, the LFP powder is placed in a material repairing agent for material repairing, and repaired LFP powder is obtained through solid-liquid separation and water washing; and S4, mixing the dried and repaired LFP powder with excessive Li2CO3 or LiOH, and carrying out regeneration sintering under the protection of a nitrogen or argon atmosphere to obtain the regenerated and repaired lithium iron phosphate powder. According to the method, the failure mechanism of the lithium iron phosphate is fully utilized, the damaged lithium iron phosphate positive electrode material is directly repaired in a wet repair mode, chemical components in the lithium iron phosphate positive electrode material are recycled to the maximum extent, and the recycling cost of the material is saved to the maximum extent.

Description

technical field [0001] The invention relates to the field of lithium battery electrode materials, in particular to a method for wet repair and regeneration of waste lithium iron phosphate positive electrode materials. Background technique [0002] With the expansion of the scale of new energy vehicles in my country, it is expected that the proportion of demand for lithium-ion batteries for electric vehicles in my country will further increase in the future. Among them, lithium iron phosphate (LiFePO 4 Or LFP) has the advantages of high thermal stability, long cycle life, and low cost, and is currently one of the most widely used cathode materials for power lithium-ion batteries. LFP batteries account for more than one-third of the overall lithium-ion battery market. With the increase in energy density and cost reduction brought about by the module-free solution represented by BYD's "blade battery", the proportion of lithium iron phosphate is expected to rebound. [0003] ...

AI Technical Summary

Problems solved by technology

However, compared with the directly prepared battery materials, due to the existence of some impurities in the repaired and regenerated battery materials, the impurities in the materials will have side reactions with the electrolyte during the charging and discharging process, thus affecting the cycle performance of the materials.

Therefore, the electrochemical performance of the battery material obtained by this method is quite different, and it is difficult to compare with commercial materials.

[0007] The lithium iron phosphate cathode material does not contain precious metals, so the economic value and environmental benefits of wet recycling and fire repair of decommissioned lithium iron phosphate batteries are not high

Images