Spinel phases, LiM1/6Mn11/6O4 (M=Co, CoAl, CoCr, CrAl), as cathodes for lithium-ion batteries

Pure and substituted spinels, LiM1/6Mn11/6O4 (M=Co, (Co,Al), (Co,Cr), (Cr,Al)), were prepared, characterised by X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS) and their cathodic performance evaluated. The Mn 2p3/2 XPS analysis shows a decrease in Mn3+ concentration by substitution. The cyclic voltammograms and the charge–discharge profiles of the M-substituted compounds show an indication of structural stabilisation, a decrease in the values of charge and discharge capacities, but a considerable improvement of capacity retention at room temperature as well as at 50 °C.