Comparison study on regeneration of spent ternary materials by molten salt solid-liquid method and traditional solid-solid method

Lithium-ion batteries (LIBs) contain a variety of toxic inorganic and organic compounds, and the spent cathode materials are high quality resources of Ni, Co, Mn, and Li elements. In this case, how to efficiently deal with spent materials has become an urgent problem. In this work, the regeneration of spent ternary materials via molten salt solid-liquid method and traditional solid-solid method are studied comparatively. Ordered and uniform crystals in MS-NCM are successfully grown in liquid medium of molten salts. The regenerated TS-NCM by traditional sintering method still presents inhomogeneous larger and smaller crystals. Moreover, only regeneration by molten salt method effectively removes F-contained impurity on the surface of spent materials, and the Ni3+ and Mn3+ on the crystal surface of MS-NCM are close to the values in commercial sample (Com-NCM). After 100 cycles at 0.2 C rate, MS-NCM and TS-NCM respectively deliver 149.1 mA h g−1 and 123.2 mA h g−1, maintaining 98.1% and 84.4% of their initial capacity. MS-NCM presenting better electrochemical performance than TS-NCM is attributed to the efficient regeneration of the spent cathode material in liquid medium of molten salts.