“…As is well known, vanadium has abundant oxidation states (0 to +5), which usually correspond to a variety of binary oxides with the general formula VO 2 + x (−0.5 x 0.5) [15,16], such as V 2 O 5 , VO 2 , V 2 O 3 , V 3 O 7 , V 4 O 9 , V 6 O 13 , etc. In the family of vanadium oxides, vanadium dioxide (VO 2 ) is a representative binary compound with different polymorphs, including VO 2 (M), VO 2 (R), VO 2 (B), * E-mail: yfzhang@dlut.edu.cn VO 2 (A), VO 2 (C), VO 2 (D), etc.…”