Structural and electrochemical characterization of Mg-doped Li1.2[Mn0.54Ni0.13Co0.13]O2 cathode material for lithium ion batteries

Magnesium doped lithium-rich cathode material Li-1.2[Mn0.54Ni0.13Co0.13](1-x)MgxO2 (x = 0, 0.005, 0.007, 0.01 and 0.012) is prepared via coprecipitation method, followed by Mg doping through dry/wet grinding and solid reaction sintering method. Among the synthesized Mg-doped materials, when x = 0.01, this material demonstrates remarkably improved cycling performance with capacity retention ratio of 83% compared to 54% of pristine one after 100 cycles at 1C rate. X-ray diffraction test of all samples shows that these materials are in the R (3) over barm (no. 166) space group and have a slight increase of the inter-slab distance with magnesium doping, which could reduce the barrier during the intercalation-deintercalation process of Li+ and stabilizes the crystal structure. The improvement in Li+ diffusion and crystal structure stability is also confirmed from the electrochemical impedance spectroscopy (EIS) analysis and cyclic voltammetry (CV) test. (C) 2015 Elsevier B.V. All rights reserved.