2003 Volume 71 Issue 8 Pages 703-709
We have been studied the relation between crystal structures, electronic structures, thermodynamic stability and cycle performances of LiMn2－xZnxO4(x=0.05, 0.10) as cathode active materials for 4 V class Li secondary battery. The crystal structures are Fd-3m and the bond lengths of (Mn, Zn)-O of LiMn1. 9Zn0.lO4 decrease in comparison with that of LiMn2O4. The cycle performance improves on increasing Zn content. The heat of dissolution of the samples was measured. These samples are more stable thermodynamically with increasing Zn content. Moreover, we calculated the net charge of each atom, the bond overlap population of Li-O, Mn-O, Zn-O, the density of states, and the electron density of Li Mn1.75M0.25O4 (M=Mn, Zn) using first principles calculation by DV-Xαmethod. Li ionicity always keeps high and the covalent bonding of Mn-O in the octahedron of LiMn1.75Zn0.25O4 is stronger than that of LiMn2O4.