Charge compensation and oxidation in NaxCoO2-delta and LixCoO2-delta studied by XANES

摘要

A comparative study on the oxidation and charge compensation in the A(x)CoO(2-delta) systems, A = Na (x = 0.75, 0.47, 0.36, 0.12) and Li (x = 1, 0.49, 0.05), using X-ray absorption spectroscopy at O 1s and Co 2p edges is reported. Both the O 1s and Co 2p XANES results show that upon removal of alkali metal from A(x)CoO(2-delta) the valence of cobalt increases more in LixCoO2-delta than in NaxCoO2-delta. In addition, the data of O 1s XANES indicate that charge compensation by oxygen is more pronounced in NaxCoO2-delta than in LixCoO2-delta. (c) 2007 Published by Elsevier Inc.