Electrochemical performance of B and M phases VO2 nanoflowers

VO2 exists in four phases, among which, the M/R phase VO2 is well known for its reversible metal-semiconductor phase transition at about 68 degrees C, and VO2 (B) is a promising candidate cathode material to be applied in aqueous lithium-ion battery owing to its proper electrode potential and layered structure. In this study, VO2 (B) nanoflowers was synthesized via one-step hydrothermal process and then successfully transformed into the VO2 (M) by heat treatment. Electrochemical behaviors of the two samples were evaluated by cycling discharge and cyclic voltammetry (CV). The results showed that flower-like VO2 (B) had the first discharge capacity of 180.33 mAhg-1, an outstanding value of 52.8% for the capacity retention after 50 cycles. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim