Direct Repair of the Crystal Structure and Coating Surface of Spent LiFePO4 Materials Enables Superfast Li-Ion Migration

• Simultaneously repairing the degraded crystal structure and reconstructing the damaged carbon coating in spent LiFePO4 cathode enables superfast lithium-ion diffusion kinetics and produces a stable cathode–electrolyte interface. • The regenerated LiFePO4 cathode delivers remarkable rate capability, low-temperature performance and compatibility in solid-state batteries. • The proposed direct regeneration approach has high economic and environmental benefits compared to hydrometallurgical and conventional direct recycling methods. • The regenerated cathode maintains capacities of 110.7 mAh g−1 (5C) and 84.1 mAh g−1 (10C) after 400 cycles, and can operate at subzero temperatures and in solid-state batteries.