A novel layered material of LiNi0.32Mn0.33Co0.33Al0.01O2 for advanced lithium-ion batteries

A novel layered material of LiNi0.32Mn0.33Co0.33Al0.01O2 with alpha-NaFeO2 structure is synthesized by sol-gel method. X-ray diffraction (XRD) shows that the cation mixing in the Li layers of it is decreased. in addition, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) are employed to characterize the reaction of lithium-ion insertion and extraction from materials. The results indicate that the structure of LiNi0.32Mn0.33Co0.33Al0.01O2 is more stable than that of the LiNi0.33Mn0.33Co0.33O2. The capacity retention of LiNi0.33Mn0.33Co0.33O2. after 40 cycles at 2.0 C is only 89.9%, however, that of the LiNi0.32Mn0.33Co0.33Al0.01O2 is improved to 97.1%. The capacity of the LiNi0.32Mn0.33Co0.33Al0.01O2 at 4.0 C remains 71.8% of the capacity at 0.2 C, while that of the LiNi0.33Mn0.33Co0.33O2 is only 54.3%. EIS measurement reveals that the increase in the charge transfer resistance during cycling is suppressed in the LiNi0.32Mn0.33Co0.33Al0.01O2 material. (C) 2009 Elsevier B.V. All rights reserved.