General behavior upon cycling of LiNiVO4 as battery electrode

X-ray absorption spectroscopy (XAS) study on the nickel and vanadium oxide LiNiVO4 gives a lot of information on the local structural changes and the redox processes involved upon lithium uptake. This paper is mainly devoted to the comparison between the behaviors of two pristine materials which differ only by the annealing temperature. The general behavior at the atomic level is identical: in a first step, a reduction and a coordination change of vanadium from tetrahedral to octahedral, then a reduction and pairing of nickel, and few changes for the main part of the lithium uptake. The reversibility is insured by vanadium which move from octahedra to tetrahedra and is reoxidized to its pristine oxidation state. From the XAS results, we may conclude that the differences in the electrochemical curves is due to side reaction with the electrolyte.