Ozone-Mediated Chemical Delithiation Reaction for Selective Li Extraction from Spent LiFePO 4

Current pyrometallurgy/hydrometallurgy recycling of lithium-ion batteries, particularly for lithium iron phosphate (LiFePO 4 ) cathodes, faces challenges such as high energy consumption, long processing cycles, and inefficient impurity separation. Here, we propose an ozone (O 3 )-mediated chemical delithiation strategy to achieve selective Li extraction from LiFePO 4 via a single-step solid-phase transformation mechanism. In-situ generated O 3 from water electrolysis oxidizes Fe(II) in the LiFePO 4 lattice to Fe(III), driving direct conversion to FePO 4, while releasing Li + to maintain charge neutrality. Benefiting from O 3 ’s strong oxidizing capability, the process achieves >99.8% lithium extraction efficiency within 45 min at room temperature, with negligible Fe dissolution. The Li 2 CO 3 and FePO 4 collected after the delithiation reaction, together with the byproduct H 2 gas from water electrolysis, can be directly used for LiFePO 4 resynthesis. This O 3 -mediated chemical delithiation reaction combines high selectivity, low energy consumption, and environmental compatibility, offering a practical route for battery recycling.