Elimination of lattice strain to reconstruct ion transport channels facilitates direct regeneration of spent LiFePO4 cathode materials

• • Lattice strain modulation via FePO4-to-Fe2P2O7 reduction reduces unit cell volume from 271.7 to 122.6 Å3, releasing residual stress and enabling continuous Li+ transport channels, which is critical for achieving high-capacity retention in regenerated cathodes. • • The phase transformation reconstructs FeO6 octahedra, significantly decreasing the migration energy barrier for Li+ within the lattice, directly addressing kinetic limitations that impede direct regeneration. • • Regenerated LiFePO4 cathodes demonstrate 80.2% capacity retention after 1000 cycles at 2C, surpassing commercial cathodes and validating the industrial viability of this pre-treatment strategy. • • The strategy eliminates Li-Fe anti-site defects, which are a major cause of capacity fade in cycled LFP, thereby restoring the structural integrity essential for long-term cycling stability.