Accurate identification of glass crystallization helps in selecting high electronic conductivity materials

Abstract

Though the current research on vanadium-based glass electrodes has made great progress, the conductivity theory of V-based glasses has not been obviously improved and crystals cannot be positioned precisely. The changes in the valence state of V3+, V4+ and V5+ are regulated by the strong reducing agent Fe2P to realize valence bond transformation of the amorphous electrode, explore the redox process of multi-electron reactions and further optimize the conductivity of electrode materials. VPFe2 and VPFe3 precipitate VO2 crystals and VPFe4 precipitates VO2 and V6O11 crystals. Electron back-scattered diffraction was used to accurately identify the distribution and specific positions of both types of crystals. V6O11 crystals exhibit a strong texture according to pole figure and inverse pole figure. XPS reveals that Fe2P and V2O5, undergo a redox reaction during the high-temperature melting process, where V5+ is reduced to V4+ and V3+ and V4+ renders a positive influence on conductivity. The addition of Fe2P increases the content of V4+ in the glass and VPFe3 glass contains the highest content of V4+, leading to the highest electronic conductivity. V2O5 transforms into VO2 crystals and VO2 transforms into V6O11 with the increase of Fe2P content. The type of nanocrystal precipitation in glass affects electronic conductivity.