Preparation and characterization of lithium manganese oxide cubic spinel Li1.03Mn1.97O4 doped with Mg and Fe

Spinel powders of Li1.03Mn1.97O4, Li1.03[MgxMn1.97−x]O4, Li1.03[FeyMn1.97−y]O4 and Li1.03[MgxFeyMn1.97−x−y]O4 systems were synthesized by sol–gel technique using lithium acetate, manganese acetate, magnesium acetate, iron nitrate and citric acid as the starting materials. The effect of Mg and Fe substitutions on the structure and surface morphology of spinel Li1.03Mn1.97O4 has been examined by X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM) and Infrared spectroscopy (IR). Electrochemical characteristics such as the cyclic performance was also investigated. The materials for all the compositions exhibit a phase pure cubic spinel structure as evident from the XRD analyses. The crystallinity and average particle size of the material increases by doping with Fe and Mg. The particles of doped samples have truncated octahedral shape. The discharge capacity of Li1.03Mn1.97O4 is 126 mAh/g. The doping increases cyclability; however, the discharge capacity reduces.