Toward Tungsten Electrodeposition at Moderate Temperatures Below 100 °C Using Chloroaluminate Ionic Liquids

The electrodeposition of tungsten at moderate temperatures (4 and WCl5 in 1-ethyl-3-methylimidazolium chloride (EMIC) and EMIC–AlCl3 ionic liquids at 80 °C–120 °C. W-rich films with a thickness of approximately 1 μm were obtained from the Lewis acidic EMIC–AlCl3–WCl5 bath, whereas the other baths did not yield any deposits. The films obtained from the EMIC–AlCl3–WCl5 bath at 80 °C had higher W contents of 54 at.% than those obtained at 120 °C. X-ray absorption near-edge structure spectra of the W-rich films indicated that W existed in an oxidized state. The findings of this study can be used as a guide to explore optimal electrolytes and electrolytic conditions for the electrodeposition of metallic W at moderate temperatures.