Sol gel synthesis of Li1+αV3O8.: 1.: From precursors to xerogel

The nature of Li(1+alpha)V(3)O(8)(.)nH(2)O gel-like precipitate and corresponding xerogels has been studied. Unlike V2O5 gel, the Li1+alphaV3O8 gels are diphasic materials made of intimately mixed solid and liquid phases having very close Li/V stoichiometry. At room temperature, the solid component contains presumably an hewettite type structure, whereas the liquid part crystallizes into lithiated decavanadic acids. Upon drying at 90 degrees C, both components lead to hydrated Li(1+alpha)V(3)O(8)(.)nH(2)O hewettite-like compounds with different interlayer spacing but with the same water content. By coupling pH measurements, X-ray diffraction, and liquid and magic-angle spinning V-51 NMR, a new mechanism of formation of the Li1+alphaV3O8 gel-like precipitate via solubilized vanadic species is proposed.