A new way to make solid state chemistry: Spark plasma synthesis of copper or silver vanadium oxide bronzes

The spark plasma sintering technique for various materials, oxides, nitrides. carbides, metals, composites, etc. is undergoing a rapid development following pioneering work in Japan. Here, the technique is used to create a new route to make solid state chemistry. The M-V-O system (M = Cu, Ag, Zn) was selected and direct interaction of M with vanadium pentoxide was performed. Remarkable syntheses theses have been achieved within minutes, paving the way for new materials. The MxV2O5 phases formed with Cu and Ag belong to the mixed valence metal-vanadium oxide bronzes whose structures and electric properties are of interest for applications as electrode materials, in lithium batteries. Their formation may also be used as a model for further investigations in order to follow the diffusion mechanisms of atoms in solids and to get a better understanding of the SPS process. In this experiment M atoms penetrate micro-crystals Of V2O5 oxide at a high speed, shearing their crystal network and rebuilding simultaneously in the mean time the crystal structure of the prototype structures beta, beta', epsilon or delta MxV2O5. (C) 2008 Published by Elsevier Masson SAS.