A facile new process for the efficient conversion of spent LiFePO4 batteries via (NH4)2S2O8-assisted mechanochemical activation coupled with water leaching

With the rapid development of the lithium-ion battery industry, safe disposal of spent LiFePO4 batteries (SLFPBs) has gradually become a focus of attention. However, the stable olivine structure of LiFePO4 prevents deconstruction and separation of the elements Li, Fe and P. Mechanochemical activation proved to be an effective and environmentally friendly method for phase deconstruction. An efficient recycling method involving (NH4)2S2O8-assisted mechanochemical activation and water leaching is reported herein for the deconstruction of SLFPBs. The results indicated that advanced oxidation of the (NH4)2S2O8 and synergistic mechanical forces accelerated the deconstruction of the LiFePO4 mineral phase. Efficient leaching of the Li and targeted enrichment of the Fe and P were achieved simultaneously while preserving the olivine structure. Under the optimal conditions, the leaching efficiency for Li was 95.3%, and the leaching efficiencies for Fe and P were both less than 1.5%. A Li2SO4 purity of 98.8% was obtained by evaporative crystallization and roasting. A 1.0 kg scale-up experiment showed that an economic profit of $4.768 was generated by recycling 1.0 kg of SLFPBs. This inexpensive, green and sustainable recycling method shows great potential for industrial planning.