Chemical and electrochemical lithiation of van der Waals oxytelluride V 2 Te 2 O †

Reversible lithium intercalation into the van der Waals phase V2Te2O, forming new phases LixV2Te2O 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.