Electrochemical Properties of Tungsten Oxide Nanowires Compared to Bulk Particles

Abstract

The electrochemical properties of oxygen-deficient tungsten oxide (W 18 O 49 ) 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 fieldemission scanning electron microscopy. The crystal structure was indexed to the monoclinic W 18 O 49 phase. The electrochemical properties of the nanowires and WO 3 bulk particles were examined by cyclic voltammetry between 2 and 4 V vs Li/Li þ . We found that the nanowires cycle better than the bulk particles. #

One-step in situ synthesis of ultrathin tungsten oxide@carbon nanowire webs as an anode material for high performance

“…The peak of 21º came from CMC 25 . 10 The open circuit voltage of these cells laid at about 3.1 V. During the first insertion process, an obvious discharge curve profile was observed for W 18 15 There were three discharge voltage plateaus (1.5, 0.6 and 0.3 V) and two charge voltage plateaus (1.1 and 1.6 V) observed in the initial discharge and charge process, which agreed well with its CV curve profile. After charge, the diffraction peaks could 10 be indexed to W 18 15 electrodes was recorded between 0.01 V and 3.0 V, as is shown in Fig.…”

“…2(g-i) showed that similar nanowire bundles with a thin carbon layer of about 0.6 nm thickness was observed for W 18 O 49 /C-2. After charge, the diffraction peaks could 10 be indexed to W 18 15 electrodes was recorded between 0.01 V and 3.0 V, as is shown in Fig. 2(j-l) showed that the aggregation of nanowire bundles was observed for W 18 85 In order to investigate the electrochemical reaction mechanism, bare W 18 O 49 and W 18 O 49 /C-1 anodes were characterized by XRD after charge and discharge.…”

“…The highest discharge capacity of 1239 mAh g −1 was obtained in the first cycle, which is significantly higher 20 than the tungsten oxide materials reported to date. Based on the behavior of these EIS spectra and the aforementioned studies, a suggested equivalent circuit for the Nyquist plots of these electrodes was 10 shown in Fig. The irreversible capacity could be assigned to the decomposition of electrolyte, forming a solid/electrolyte interphase on the 25 electrode surface, and leading to the irreversible insertion of lithium ions into W 18 O 49 host 27 .…”

“…We reported a novel ulthathin W 18 O 49 @carbon nanowire web anode material for high performance lithium-ion batteries which 10 was synthesized via a facile one-step solvothermal method. Carbon layer was uniformly coated on ulthathin W 18 …”

Insulator-to-metal transition of WO3 epitaxial films induced by electrochemical Li-ion intercalation

“…1,2) WO 3 with a distorted ReO 3 -type structure can be regarded as an A-site deficient perovskite, being capable of a host material for intercalations of alkaline and alkaline-earth metals. [3][4][5][6][7] Smaller H and Li atoms are easily intercalated to the amorphous or polycrystalline films, and the resultant doping electrons color WO 3 . Because coloration of A x WO 3 is attributed to increasing number of electrons in the W 5d states, it will be associated with an electronic phase transition such as insulator to metal transition (IMT).…”