Mg-doped Li1.2Mn0.54Ni0.13Co0.13O2 nano flakes with improved electrochemical performance for lithium-ion battery application

Mg-doped Li1.2-xMgxMn0.54Ni0.13Co0.13O2 cathode materials were prepared by a molten salt method. Our results showed that the introduction of NaCl is rather important and will provide a fusion environment, which not only leads to an evenly distribution of the transition metals within the cathode materials but is also helpful for the formation of a unique two dimensional (2D) nano structures. Mg doping results in a structural variation of the cathode materials, leading to a continuous increase of the capacity at the first dozen cycles. Although Mg doping can significantly improve the rate capability, the cycling stability, and the capacity retention of the cathode materials, a large Mg doping amount (>6%) will cause the formation of impurity phases, which in turn reduce the electrochemical performance of the materials. Electrochemical impedance spectroscopy (EIS) measurement showed that the charge transfer resistance was reduced significantly due to Mg doping, and 4% Mg-doped sample exhibits promising lithium diffusion kinetics and rate capability.