Doped Nanoscale NMC333 as Cathode Materials for Li-Ion Batteries

A series of Li(Ni(1/3)Mn(1/3)Co(1/3))(1−x)M(x)O(2) (M = Al, Mg, Zn, and Fe, x = 0.06) was prepared via sol-gel method assisted by ethylene diamine tetra acetic acid as a chelating agent. A typical hexagonal α-NaFeO(2) structure (R-3m space group) was observed for parent and doped samples as revealed by X-ray diffraction patterns. For all samples, hexagonally shaped nanoparticles were observed by scanning electron microscopy and transmission electron microscopy. The local structure was characterized by infrared, Raman, and Mössbauer spectroscopy and (7)Li nuclear magnetic resonance (Li-NMR). Cyclic voltammetry and galvanostatic charge-discharge tests showed that Mg and Al doping improved the electrochemical performance of LiNi(1/3)Mn(1/3)Co(1/3)O(2) in terms of specific capacities and cyclability. In addition, while Al doping increases the initial capacity, Mg doping is the best choice as it improves cyclability for reasons discussed in this work.