In this study, vertical nanowire arrays of MoO 3-x grown on metallic substrates with diameters of ∼90 nm show high-capacity retention of ∼630 mAhg -1 for up to 20 cycles at 50 mAg -1 current density. Particularly, they exhibit a capacity retention of ∼500 mAhg -1 in the voltage window of 0.7-0.1 V, much higher than the theoretical capacity of graphite. In addition, 10 nm Si-coated MoO 3-x nanowire arrays have shown a capacity retention of ∼780 mAhg -1, indicating that hybrid materials are the next generation materials for lithium ion batteries. © 2012 American Chemical Society.