Lithium insertion property of Li22V2O5•nH2O

Lithium vanadium oxides have been prepared by the new solution processing in an aqueous hydrogen peroxide solution with lithium and vanadium alkoxides, LiO-n-C3H7 and VO(O-i-C3H7)(3), at low temperature, compared with conventional high temperature solid state reaction. Oxides having a layered structure isomorphic to that of gamma-phase LixV2O5 were obtained. This "gamma-like phase" oxide can be obtained at the nominal Li/V ratio of 1.5 almost as a single phase. However, formation of omega phase cannot be confirmed. They-like phase oxide contained water and organic compounds, and the water content n in LixV2O5 center dot nH(2)O was found to be about 2.4 for the gamma-like phase oxide. Further as the result of the atomic absorption spectrometric method, the lithium content x in LixV2O5 center dot nH(2)O was estimated to be 2.2, and water molecules presumably exist in the interlayer space. Water content of the gamma-like phase oxides, affects charge and discharge behaviours markedly. The lithium extraction-insertion capacity of the gamma-like phase oxides were smaller, but the oxides had higher average potential compared with those of gamma-phase oxide. As water content of gamma-like phase oxides decreased, the lithium extraction-insertion capacity increased. Moreover, it should be noted that the average potential of gamma-like phase oxides is at least 1 V higher than that of gamma-LiV2O5. (c) 2006 Elsevier Ltd. All rights reserved.