Cobalt-free Li-Rich 0.1Li₂MnO₃•0.9LiNi_0.56Mn_0.44O₂ with High Performances as Cathode Material for Lithium-ion Batteries

The cobalt-free Li-rich layered oxide 0.1Li₂MnO₃·0.9LiNi_0.56Mn_0.44O₂ is successfully synthesized by a coprecipition method followed by high-temperature calcinations. The compostions and structures of the material have been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and the results revealed that the sample possesses typical α-NaFeO₂ layered structure with a weak reflection of LiMnO₆, and of microspheres with porous surface. Electrochemical measurements showed that the cobalt-free Li-rich sample delivers good cycling stability and rate capability with initial discharge capacity of 263, 173, 137 and 57 mAh g^-1 at different current density of 50, 160, 320 and 640 mA g^-1, respectively. The electrochemical performances of the cobalt-free Li-rich 0.1Li₂MnO₃·0.9LiNi_0.56Mn_0.44O₂ could be related to not only the synergistic effect of specific morphology and appropriate size but also the porous surface. (paper)