Study on selective recovery of lithium ions from lithium iron phosphate powder by electrochemical method

Abstract

In recent years, electric vehicle is greatly flourishing, while lithium iron phosphate batteries are vigorously developed due to their low cost and high stability. Since it is expected that the first batch of lithium iron phosphate (LFP) batteries will be retired at the peak in 2025, it is crucial to develop an environmentally and efficient recycling method. In this study, an acid-assisted electrochemical extraction method of lithium ions from LFP powder was proposed. Part of the LFP powder was leached directly by acid, and the leached ferrous ions were separated by oxidation precipitation and electroplating. The remaining LFP powder was directly oxidized by the anode to release lithium ions. The leaching efficiency of lithium ion reached up to 99.89 % and the leaching efficiency of iron ion was kept at a very low value of less than 0.2 %. The selective separation of lithium ion can be efficiently achieved during the leaching process. After evaporation and concentration, the lithium ions were recovered as product of high-purity lithium phosphate. Compared with other recycling methods, the proposed recovery method used less reagents and generated little waste. This process presents a novel green recycling pathway for the potentially selective leaching and recovery of spent LFP batteries.