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 (LiFePO4) cathodes, faces challenges such as high energy consumption, long processing cycles, and inefficient impurity separation. Here, we propose an ozone (O3)-mediated chemical delithiation strategy to achieve selective Li extraction from LiFePO4 via a single-step solid-phase transformation mechanism. In-situ generated O3 from water electrolysis oxidizes Fe(II) in the LiFePO4 lattice to Fe(III), driving direct conversion to FePO4, while releasing Li+ to maintain charge neutrality. Benefiting from O3’s strong oxidizing capability, the process achieves >99.8% lithium extraction efficiency within 45 min at room temperature, with negligible Fe dissolution. The Li2CO3 and FePO4 collected after the delithiation reaction, together with the byproduct H2 gas from water electrolysis, can be directly used for LiFePO4 resynthesis. This O3-mediated chemical delithiation reaction combines high selectivity, low energy consumption, and environmental compatibility, offering a practical route for battery recycling.