Regenerating of LiNi0.5Co0.2Mn0.3O2 cathode materials from spent lithium-ion batteries

Abstract

An acidless process route for regenerating LiNi0.5Co0.2Mn0.3O2 materials is applied in this work. The regenerated LiNi0.5Co0.2Mn0.3O2 materials are prepared by calcining the mixture of LiOH·H2O and the spent LiNi0.5Co0.2Mn0.3O2 materials. The regeneration process with different ratio of Li/List (Li content in commercial LiNi0.5Co0.2Mn0.3O2) from 12 to 16% is extensively investigated. Remarkably, the regenerated materials with Li/List for 14% possesses optimal discharge capacity (161.25 mAh g− 1 at 0.1 °C), enhanced rate performance and cycling stability (with capacity retention of 95.29% after cycling at 0.5 °C for 50 cycles) compared to spent LiNi0.5Co0.2Mn0.3O2 (with initial capacity of 40.35 mAh g− 1 and retention of 79.55% after cycling at 0.5 °C for 50 cycles). The Rietveld refinement, X-ray photoelectron spectroscopy (XPS) and further Electrochemical impedance spectroscopy (EIS) indicate these improved electrochemical performance can be account for the increase of active lithium, lower cation mixing degree and impedance. The results indicate the approach to regenerating of LiNi0.5Co0.2Mn0.3O2 is feasible.