Lithium insertion property of Li2 2V2O5·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 -C 3 H 7 and VO(O- i -C 3 H 7 ) 3 , at low temperature, compared with conventional high temperature solid state reaction. Oxides having a layered structure isomorphic to that of γ-phase Li x V 2 O 5 were obtained. This “γ-like phase” oxide can be obtained at the nominal Li/V ratio of 1.5 almost as a single phase. However, formation of ω phase cannot be confirmed. The γ-like phase oxide contained water and organic compounds, and the water content n in Li x V 2 O 5 · n H 2 O was found to be about 2.4 for the γ-like phase oxide. Further as the result of the atomic absorption spectrometric method, the lithium content x in Li x V 2 O 5 · n H 2 O was estimated to be 2.2, and water molecules presumably exist in the interlayer space. Water content of the γ-like phase oxides, affects charge and discharge behaviours markedly. The lithium extraction–insertion capacity of the γ-like phase oxides were smaller, but the oxides had higher average potential compared with those of γ-phase oxide. As water content of γ-like phase oxides decreased, the lithium extraction–insertion capacity increased. Moreover, it should be noted that the average potential of γ-like phase oxides is at least 1 V higher than that of γ-LiV 2 O 5 .