Crystal structure of the end product of electrochemical lithium intercalation in V2(SO4)3

Abstract

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 material via rearrangement of strong 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 of the order of minutes, indicate that the rearrangement is reversible, at least during the first cycle.