Reduction Processes in the Course of Mechanochemical Synthesis of Li1+xV3O8

Abstract

Mechanical activation (MA) of the LiOH+V2O5 and Li2CO3+V2O5 mixtures followed by brief heating at 673 K was used to prepare dispersed Li1+xV3O8. It was shown that structural transformations during MA are accompanied by reduction processes. EPR spectra of Li1+xV3O8 are attributed to vanadyl VO2+ ions with weak exchange interaction. The interaction of localized electrons (V4+ ions) with electron gas (delocalized electrons), which is exhibited through 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 relaxation is different for intermediate and final products. The properties of mechanochemically 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.