Deoxidization of V 2 O 5 Powder into VO 2 Assisted by an Electrochemical Lithium Intercalation Technique

This article demonstrates a method to fabricate VO 2 powder by annealing a precursor that was obtained by electrochemical intercalation of lithium into layered structured V 2 O 5 . The method includes three steps. First, Li + was intercalated into interlayers of V 2 O 5 through an electrochemical process with precisely controlled electrical discharging currents and intercalation amounts, and at the same time V 5+ would be deoxidized into V 4+ . Secondly, the Li + ‐intercalated powder was rinsed in an acid solution to achieve an ion exchanging process of replacing the Li + in the V–O frame with H + . Thirdly, the powder was annealed at 800°C in N 2 atmosphere for dehydration and VO 2 crystallization. By DSC investigation, the as‐produced final product has a strong endothermic peak at around 68°C in a heating semicycle, which is indicative of the phase transition from VO 2 ( M ) to VO 2 ( R ). This approach can be extended to the fabrication of other sub‐valence oxides by lithium intercalation and deoxidization of its higher valence layer‐structured precursors.