Synthesis and electrochemical properties of Li[Ni0.4Co0.2Mn(0.4-x)Mgx]O2-yFy via a carbonate co-precipitation

Abstract

Magnesium doped transition metal-layered compounds, Li[Ni0.4Co0.2Mn(0.4-x)Mgx]O2-yFy (x = 0, 0.04, y = 0, 0.08) have been synthesized by a carbonate co-precipitation method. X-ray diffraction patterns revealed that this material has a typical layered structure with R (3) over barm space group. Spherical morphologies and mono-dispersed (approximately 15 mu m) powders were observed by scanning electron microscopy. Mg and F substitutions were effective for the improvement of physical properties. These improved physical characteristics enhanced the capacity retention and thermal stability, even though the electrodes were cycled between 2.8 and 4.6 V.