Electrochimica Acta, Vol.52, No.7, 2657-2660, 2007
Lithium insertion property of Li(22)V(2)O(5 center dot)nH(2)O
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.
Keywords:lithium vanadium oxide;lithium insertion;solution processing;charge and discharge;gamma-LiV2O5