1 Introduction Recycling spent lithium-ion batteries (LIBs) is essential to mitigate the environmental impact of battery disposal and extraction of raw materials for their production [1-5]. Traditional metallurgical recycling methods, which convert spent LIB cathodes into their elemental components, consume significant energy and raise environmental concerns [5-7]. LiFePO4 (LFP) is emerging as a dominant cathode material and will be a major component in end-of-life LIB waste [8-10].