Resynthesis of Ni-rich lithium nickel manganese cobalt oxide cathode materials from the industrial leachate of spent Li-ion batteries: The effect of PF6− species from electrolyte

Abstract

A significant rise in the generation of spent Li-ion batteries (LIBs) is expected due to the widespread usage of LIBs in various applications. The benefit of spent LIB valorization can be maximized by a high value-added recycling process. The resynthesis of cathode active materials (CAMs), a promising recycling method that directly produces CAMs from LIB leachate, is explored in this study. We resynthesize Ni-rich LiNi0.9Co0.05Mn0.05O2 (NCM955) CAMs via coprecipitation and sintering by varying the amount of PF6−, which can raise environmental concerns, in industrial LIB leachate. Our first employment of glow discharge mass spectrometer in the investigation of PF6− decomposition behavior reveals that the small amounts of PO43− are precipitated into NCM precursors and F− remains in the leachate during resynthesis process. The incorporation of PF6− species during the coprecipitation results in an enlargement of crystal lattice parameters. The incorporated PF6− species increases the ratio of Ni2+ to Ni3+ and leads to the formation of LixPOyFz on the surface of NCM, which exerts a positive effect on the overall LIB performance. This study is the first attempt where the effect of PF6− species from LIB electrolyte is investigated in the resynthesis of the state-of-the-art NCM955 from industrial LIB leachate.