Efficient regeneration of LiFePO4 through low-temperature roasting with ammonium bisulfate for spent LiFePO4 cathode scraps

The development of sustainable recycling technologies for spent lithium iron phosphate (LiFePO 4 ) batteries is crucial to address critical challenges in resource scarcity and environmental sustainability. Herein, we present an improved pyrometallurgical method utilizing ammonium bisulfate (NH 4 HSO 4 )-assisted low-temperature roasting for efficient lithium recovery. Through systematic optimization, the roasting of spent LiFePO 4 (S-LFP) cathodes with NH 4 HSO 4 at 300 °C for 3 h followed by water leaching achieves 98.5 % lithium recovery efficiency while maintaining a low iron leaching of 4.6 %. Furthermore, the regenerated LiFePO 4 (R-LFP) cathode material synthesized from recycled FePO 4 and Li 2 CO 3 precursors exhibits excellent electrochemical performance, retaining the discharge capacity of 140.5 mAh g −1 after 200 cycles at 1 C rate. Compared with conventional recycling methods, this process eliminates hazardous acid/base consumption and reduces energy requirements through lower operational temperatures. Our findings provide a practical pathway for closed-loop recycling of LiFePO 4 batteries while addressing both economic viability and environmental concerns in lithium-ion battery sustainability.