Resynthesis and electrochemical performance of LiNi0.5Co0.2Mn0.3O2 from spent cathode material of lithium-ion batteries

Abstract

LiNi0.5Co0.2Mn0.3O2 (LNCM) was resynthesized by a novel metallurgical approach coupled with solid-state sintering using cathode materials from spent lithium-ion batteries (LIBs) as starting materials. A combination of reduction roasting, two-step leaching, co-precipitation, and solid-state reaction was applied to recover valuable metals and regenerate cathode materials. The prepared LNCM was characterized by a series of physical and electrochemical measurements for comparison with commercial LNCM. X-ray diffraction and scanning electron microscopy results indicate that the resynthesized LNCM exhibits good layered structure and a sphere of approximately 6 μm. The electrochemical tests indicate that the resynthesized LNCM has an initial discharge capacity of 172.9 mA h g-1 (0.2 C) between 2.5 and 4.3 V; the discharge capacity is 160.9 mA h g-1 (0.2 C) after 50 cycles, in which the capacity retention is 93.8%. Cyclic voltammograms and electrochemical impedance spectra detected that resynthesized LNCM has good structural reversibility and conductivity, similar to commercial LNCM. This method is feasible for regenerating the spent cathode material of LIBs, which can contribute to both resource recycling and environmental protection.