Structural characterization of layered LiNi0.85-xMnxCo0.15O2 with x=0, 0.1, 0.2 and 0.4 oxide electrodes for Li batteries

We report the synthesis of LiNi0.85-xCo0.15MnxO2 positive electrode materials from Ni0.85-xCo0.15Mnx(OH)(2) and Li2CO3. XRD and XPS are used to study the effect of Mn-doping on the microstructures and oxidation states of the LiNi0.85-xCo0.15MnxO2 materials. The analysis shows that Mn-doping promotes the formation of a single phase. With increasing substitution of Mn ions for Ni ions, the lattice parameter a decreases, while the lattice parameters c and c/a increase. XPS revealed that the oxidation states of Ni, Co and Mn in LiNi0.85-xCo0.15MnxO2 compounds (where x = 0.1, 0.2 and 0.4) were +2/+3, +3 and +4. The substitution of Mn ions for Ni ions induces a decrease in the average oxidation state of Ni. Because the substitution of Mn for Ni ions is complex, the extent of the changes between the lattice parameter and LM-O differ. The occupation of Ni in Li sites is affected by the ordering of Mn4+ with Ni2+ and Mn4+ with Li+. (C) 2011 Elsevier B.V. All rights reserved.