Chemical and electrochemical lithiation of van der Waals oxytelluride V2Te2O†

Reversible lithium intercalation into the van der Waals phase V₂Te₂O, forming new phases Li_xV₂Te₂O with x approaching 2, is reported using both chemical and electrochemical methods. The progress of each reaction was followed using powder X-ray diffraction and the crystal structure of the intercalated phase with x = 1, LiV₂Te₂O, was refined using powder neutron diffraction. The intercalated Li ions occupy vacant pseudo-octahedral sites and the unit cell expands on reduction with no change in symmetry. The lithium ions can be removed chemically or electrochemically, making this the first known oxytelluride to undergo reversible lithium intercalation.