Alternating current impedance and Raman spectroscopic study on electrochromic a-WO3 films

Abstract

The chemical diffusion of lithium ions in a-LixWO3 films is investigated using alternating current impedance spectroscopy and Raman scattering measurements. The diffusion coefficients increase with increasing x in a-LixWO3 up to x=0.072 and then decrease. Raman measurements show that the W6+=O/O–W6+–O ratio also increases at the early stage of lithium insertion and then decreases with further lithium insertion. We conclude that the diffusion kinetics of lithium ions in a-LixWO3 films is very closely related to the W6+=O/O–W6+–O ratio.

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“…(Table 2 and Figure 7). is attributed to W=O bonds [11,[29][30][31]. A c c e p t e d M a n u s c r i p t Figure 8: Raman spectra of a dense film before (no Li + ), after Li + intercalation and Li + de-intercalation…”

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