Performance of Al-doped LiNi1/3Co1/3Mn1/3O2 synthesized from spent lithium ion batteries by sol-gel method

摘要

LiNi1/3-xCo1/3Mn1/3AlxO2 (x = 0.02, 0.04) have been synthesized by sol-gel method using spent lithium ion batteries (LIBs) as a raw material. The effect of Al3+ doping on the structure and electrochemical performances of LiNi1/3Co1/3Mn1/3O2 were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope-energy dispersive X-ray spectroscopy (TEM-EDX) mapping, X-ray photoelectron spectroscopy (XPS), charge-discharge cycling, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Results show that the Al-doped LiNi1/3Co1/3Mn1/3O2 exhibits a typical layered structure based on hexagonal alpha-NaFeO2 with space group of r-3m, and the doped Al3+ has a certain effect on inhibiting the mixing of cations. The synthesized LiNi1/3-0.02Co1/3Mn1/3Al0.02O2 maintains a high reversible discharge capacity of 154.9 mAhg(-1) after 100 cycles at the current density of 0.2C, which is 14.3% times higher than that of LiNi1/3Co1/3Mn1/3O2. LiNi1/3-0.02Co1/3Mn1/3Al0.02O2 also displays a good rate performance with 112.8 mAhg(-1) at the current density of 2C. The high reversible specific capacity and good rate capability demonstrates that the one-step acid leaching and reuse of valuable metals in the spent LIBs is efficient and feasible.