Regeneration of LiFePO4 from Spent Materials: Control and Influence of Al Impurity

Abstract Owing to the rapid increase of lithium iron phosphate (LiFePO 4 ) batteries, recycling and regeneration of LiFePO 4 enjoys significances for sustainable development and environmental protection. In this study, an effective regeneration method for spent LiFePO 4 materials and the influence of Al impurity on the electrochemical performance of regenerated LiFePO 4 were studied. Firstly, 99.26 % Fe, 99.52 % P, 99.58 % Li, 59.36 % Al and 20.24 % Cu in spent LiFePO 4 material were leached with 150 g ⋅ L −1 H 2 SO 4 . Subsequently, Al removal and control were achieved by simply adjusting the pH value, and FePO 4 ⋅ 2H 2 O precursors with different Al contents were prepared. Specially, the LiFePO 4 regenerated by FePO 4 ⋅ 2H 2 O precursor containing 0.096 % Al exhibits excellent electrochemical performance with discharge capacity of 145 mAh ⋅ g −1 , 140.5 mAh ⋅ g −1 and 130.9 mAh ⋅ g −1 at the current density of 1 C, 2 C and 5 C, respectively.