'Chimie douce' synthesis and electrochemical properties of amorphous and crystallized LiNiVO4 vs. Li

Amorphous LiNiVO4 has been synthesized by a new 'chimie douce' method, which consists of precipitation reaction occurring at a well-defined pH. This new amorphous lithiated vanadate was shown, by means of thermal analyses and X-ray powder diffraction. to progressively crystallize in the spinel-type structure upon increasing the annealing temperature from 200 degrees C to 700 degrees C. Both amorphous and crystallized LiNiVO4 can reversibly react with 7 Li per formula unit, similar to the compounds synthesized by the classical high temperature route. To understand the chemical transformations occurring during the Li uptake/removal in crystallized LiNiVO4, and thereby to throw some light on the origin of the large capacity of those materials, in-situ XRD measurements have been performed.