An environmentally friendly and facile approach to recycle spent LiFePO4 for resynthesizing LiFePO4/C materials

Abstract

With the large-scale application of LFP batteries, the number of scrapped batteries has increased, leading to concerns regarding resource wastage and environmental pollution. In this paper, we recycle spent LFP by means of isomorphic-induced displacement and solvent extraction methods. The leaching agent is FeCl₃, and Fe²⁺ in the leaching solution can be further oxidized and cyclically utilized, effectively avoids the generation of vast acidic wastewater associated with traditional acid leaching. Moreover, TBP, in combination with FeCl₄⁻, underscores the pivotal role of synergistic extractants in the extraction mechanism. The results show that leaching and extraction rates of lithium are tested to be 98% and 97%. Subsequently, Li⁺ is further extracted from the leaching solution to form Li₂CO₃. A preliminary economic assessment is performed for the recovery of 10 g spent LFP powder, revealing that the total profit generated from the entire process is 0.106 USD and holding economic feasibility. Finally, the high-performance LiFePO₄/C material is synthesized by a simple solid-phase method, achieving a closed-loop process. Materials reveal 145.97 mAh/g with 0.1 C and exhibit 99.80% retention after 100 cycles. This investigation offers new perspectives and revealing valuable references in recycling LFP from spent lithium batteries.