Abstract: Chemical delithiated LixCoO2 (x=1, 0.7, 0.66 and 0.57) has been synthesized by using a strong oxidant, NaS2O8. The structure investigations indicate that all the samples remain with hexagonal cells, which have expansion of c axis during Li extraction. Transmission electron microscopy (TEM) observations revealed the presence of superstructures arising from intercalated Li-ordering corresponding to first-principle calculations. The measurements of the physical properties are also influenced by Li concentration.

Key words: LixCoO2, delithiated, Li-ordering