Spin-Coated V₂O₅ Xerogel Thin Films. 1. Microstructure and Morphology

Vanadium pentoxide xerogel films spin-coated on nickel/silicon substrates have shown high electrochemical performance. In fact, more than 3 equiv of lithium V₂O₅ unit can be reversibly inserted between 3.5 and 1.6 V in aprotic electrolytes. The high insertion capacity coupled with the inexpensive and well-known preparation procedure make the material interesting for thin-film lithium battery and electrochromic device applications. In the present paper we report the characterization of such thin films based on X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), quartz crystal microbalance, optical, and electronic conductivity measurements. The spin-coated films are highly amorphous, with a small amount of ribbon stacking that is randomly oriented. The disorder is caused by the joint effect of high shear and rapid drying during spin coating.