Synthesis, Structure And Properties Of V₂O₅ Nanocomposite Films Modified With Polymer

The synthesis, structure, properties and interface behavior of nanocomposite materials based on layered V2O5 and MoO3, which can be topotactically reacted with alkali-metal ions ( Li+, Na⁺, etc. ) have attracted more attention in recent years. The intercalation of polymer into the interlayer is expected to improve the interface and interlayer structure of these materials, resulting in desirable novel characteristics. In this dissertation, vanadium pentoxide sols were synthesized by melt quenching in oxygen atmosphere. (PEO).TV2O₅ ?nH2O(X=0,0.5,l,2) nanocomposite films were prepared by solution direct intercalation of PEO via sol-gel route. Meantime, the structure and properties of the films were investigated.The contrast analysis of V2Os xerogel prepared in different atmosphere show that V₂Os xerogel prepared in oxygen atmosphere has better noncrystallization, higher content of V5+ ions, ideal structure and higher Li+ insertion capacity than that prepared in air.The results of XRD, TG/DTA show that the (001) crystal plane distance of (PEO)_x V2O5 ?nH20 (x=0, 0.5, 1, 2) nanocomposite films increases from 1.1950nm at x=0 to 1.5173nm at x=2 after heat-treatment. PEO can be completely intercalated into the interlayer of V2O5 xerogel in form of amorphous state at x=0.5, whereas partial PEO can not be intercalated into V2Os xerogel interlayer and exists outside of V2O5 xerogel interlayer in form of crystalline state at x=l,2. The SEM and AFM micrographs of xerogel thin films show that the surface of the films is homogeneous, no cracks and holes are observed.The IR analysis indicate that all vibrational modes change remarkably after PEO was intercalated into V2O5 xerogel interlayer, due to the strong interaction between polymer and inorganic framework. The stretching vibration of V=O shifts to lower wavenumbers, which is contributed to the Oet V:=O bonding interaction.The intercalation of PEO effectively shields the electrostatic interaction between Li+ ions and V2O5 layers, resulting in the improvement of the cycling reversibility and stability of Li+ ions insertion/extraction in the interlayer of V2O5 xerogel and the improvement of electrochromic behavior of the films.This work was supported by the National Natural Science Foundation of China (Grant No. 59802009 and No. 50172036).