• • Direct regeneration via hydrothermal synthesis using Na2SO3 as a reducing agent in Li2SO4 solution achieved a reversible specific capacity of 135.9 mAh/g at 1C, with 99% capacity retention after 100 cycles, demonstrating economic viability and cycling stability.
• • Pyrometallurgical recovery typically requires temperatures above 800°C, leading to high energy consumption and hazardous gas emissions; however, NaOH/Na2CO3 activation enables decomposition of Fe-PO4 bonds at 600°C/900°C, reducing energy demand.
• • Hydrometallurgical processes, the mainstream route, involve leaching, purification, and product synthesis; challenges remain in deep removal of impurities like Al, Ti, and F, which degrade product quality.
• • The review highlights that current recovery often prioritizes lithium over iron and phosphorus, resulting in insufficient high-value utilization of Fe/P resources; innovative approaches such as converting delithiated LiFePO4 into NaFeS2 are proposed to address this.