The electrochemical properties of oxygen-deficient tungsten oxide (W18O49) nanowires were investigated. The nanowires were prepared via a simple thermal evaporation method. The as-deposited nanowires were 60-90 nm in diameter and several micrometers long as measured by field-emission scanning electron microscopy. The crystal structure was indexed to the monoclinic W18O49 phase. The electrochemical properties of the nanowires and WO3 bulk particles were examined by cyclic voltammetry between 2 and 4 V vs Li/Li+. We found that the nanowires cycle better than the bulk particles. (C) 2012 The Japan Society of Applied Physics