Recent progress in sustainable recycling of LiFePO4-type lithium-ion batteries: Strategies for highly selective lithium recovery

Abstract

The demand for LiFePO4 (LFP)-type batteries have increased remarkably in energy storage devices due to a longer life span, improved discharge and charge efficiency, and safe handling. The growing use of such batteries has raised concern about their proper disposal, where improper handling might result in hazardous material entering the environment. As a result, waste LFP battery recycling is receiving a lot of attention. To date, the recycling of spent LFP batteries has been carried with two traditional methods: (1) pyrometallurgy (i.e., direct regeneration) and (2) hydrometallurgy (i.e., the leaching of individual metals). However, the toxic off-gassing at high temperatures were eventually found not in favor of the environment. Besides, hydrometallurgical recovery of complete metal ions (i.e., Li, Fe, and P) in solution increases the cost of the process due to excess use of minerals. To this end, a hydrometallurgical derived process commonly known as one-step selective recovery of Li and FePO4 are keenly focused, where in-situ recovery of Li in leaching solution and Fe as FePO4 in residue are followed. This review is directed to the selective recovery of Li from the spent LFP cathode materials. The discussion centers on the present process of selective recovery in comparison to the traditional approaches. The structure of LFP and Li-recovery routes, which involve various kinds of leaching agents, are discussed. The effective separation procedures and their advancement are examined, which may pave the way for new and updated technologies to increase environmentally friendly recycling routes. Finally, endeavors are given to the challenges and future aspects of recycling LFP cathode materials. In general, the review will aid in understanding the evolution of a sustainable Li-ion battery recycling methods.