CRYSTAL STRUCTURE OF THE END PRODUCT OF THE FIRST CYCLE ELECTROCHEMICAL LITHIUM INTERCALATION IN V2(SO4)3
Gavin Vaughan1, Joel Gaubicher1, Thierry Le Mercier1, Jacques Angenault2, Michel Quarton1, and Yves Chabre3
1ESRF, BP 220 38043 Grenoble Cedex
France
2Laboratoire de Cristallochimie du
Solide, Universite Pierre et Marie Curie-Paris VI, URA-CNRS 1388,
4 place Jussieu, 75252 Paris Cedex 05, France
3Laboratoire de Spectroscopie
Physique, Universite Grenoble I, St. Martin d'Heres, France.
The crystal structure of Li2V2(SO4)3, obtained by electrochemical intercalation of lithium into V2(SO4)3, has been solved using high resolution synchrotron x-ray powder diffraction. Surprisingly, in light of its ``soft chemistry'' synthesis, the structure of Li2V2(SO4)3 is derived from that of the starting product via rearrangement of covalent V-O bonds, leading to a mixed corner sharing / edge sharing arrangement among the VO6 octahedra and SO4 tetrahedra. Results of in-situ electrochemical Li intercalation/ synchrotron powder diffraction studies, carried out in working batteries and with a time resolution on the order of minutes, indicate furthermore that the rearrangement is reversible, at least during the first cycle.