Room temperature efficient regeneration of spent LiFePO4 by direct chemical lithiation

Herein, we report a direct recycling process of the spent LiFePO4 by direct room temperature chemical lithiation. A fine characterization of a recovered LFP cathode from a spent commercial battery demonstrates that the end of life of the battery is mainly due to the lithium loss, while the structure of the LFP cathode material is globally preserved. It is shown here that such a cathode can be efficiently recovered by direct lithiation in solution using LiI in different solvents (acetonitrile, ethanol, cyclohexane, methanol, DMSO and propan-1,2-ol) with optimized experimental parameters. The best electrochemical performance is obtained with ethanol, one of the greenest and cheapest solvents, without any additional heat treatment. More interestingly, the regeneration of LFP can be achieved directly with the material cast onto its aluminum collector, which paves the way to more efficient recycling preserving the whole electrode formulation and avoiding a new electrode casting. The chemically lithiated LFP cathode in ethanol exhibits a full reversible capacity of ∼168 mAh/g vs. Li metal with a stable coulombic efficiency exceeding 98% for 25 cycles. In addition, this recovery process produces regenerated electrodes showing good electrochemical performance also at high current density.