鈥淚n Operando鈥?X-ray Absorption Spectroscopy Analysis of Structural Changes During Electrochemical Cycling of WO3 and WxSiyOz Amorphous

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• 作者：F. J. Garcia-Garcia ; J. Gil-Rostra ; F. Yubero ; J. P. Espin贸s ; A. R. Gonzalez-Elipe ; J. Chaboy
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：January 8, 2015
• 年：2015
• 卷：119
• 期：1
• 页码：644-652
• 全文大小：447K
• ISSN：1932-7455

文摘

This work reports a X-ray absorption spectroscopy (XAS) study under 鈥渋n operando鈥?conditions of the structural and chemical changes undergone by WO₃ and W_xSi_yO_z thin films used as electrochromic cathodes. The electrochromic films were prepared by magnetron sputtering deposition at oblique angles and then characterized by a large variety of techniques. The voltammograms and chronoamperometric diagrams in both aqueous and organic electrolyte media revealed a total reversibility of the electrochromic behavior, a low response time, and a high coloration efficiency for the two types of thin films. The 鈥渋n operando鈥?X-ray absorption study of the films working in aqueous solutions revealed that when they were electrochemically cycled the average W鈥揙 distances reversibly varied by a 螖d of 0.06 and 0.08 脜 for, respectively, WO₃ and W_xSi_yO_z. These changes are discussed by assuming the reduction of W⁶⁺ cations and the transformation of W鈺怬 double bonds into single W鈥揙 bond structures during the electrochemical cycling of the films.