Reduction processes in the course of mechanochemical synthesis of Li1+xV3O8

Mechanical activation (MA) of the LiOH + V2O5 and Li2CO3 + V2O5 mixtures fo llowed by brief heating at 673 K was used to prepare dispersed Li1+xV3O8. I t was shown that structural transformations during MA are accompanied by re duction processes. EPR spectra of Li1+xV3O8 are attributed to vanadyl VO2ions with weak exchange interaction. The interaction of localized electrons (V4+ ions) with electron gas (delocalized electrons), which is exhibited t hrough the dependence of EPR line width of vanadium ions versus measurement temperature (C-S-C relaxation), is revealed. It is shown that C-S-C relaxa tion is different for intermediate and final products. The properties of me chanochemically prepared Li1+xV3O8 are compared with those of HT-Li1+xV3O8, obtained by conventional solid state reaction. Mechanochemically prepared Li1+xV3O8 is characterized by a similar amount of vanadium ions, producing electron gas, but a higher specific surface area. (C) 2001 Academic Press.