Structural, optical, thermal and conducting properties of V2−xLixO5−δ (0.15 ≤ x ≤ 0.30) systems
Savidh Khan, K. Singh
Abstract
Abstract Lithium-doped vanadates (V 2− x Li x O 5− δ (0.15 ≤ x ≤ 0.30)) are synthesized by melt-quench method. The physical, structural, optical, thermal and conducting properties of as-quenched samples are investigated using various experimental techniques to study their suitability for electrolyte in battery/solid oxide fuel cell application. X-ray diffraction (XRD) patterns confirm the formation of three different crystalline phases. FTIR and Raman spectra indicate that the doping of Li 2 O into V 2 O 5 leads to a transition from VO 5 into VO 4 structural unit. The optical diffused reflectance spectra revealed that the optical band gap ( E g ) decreases from 2.2 to 2.08 eV while Urbach energy ( E U ) increases (0.31–0.41 eV) with the addition of Li 2 O content in place of vanadium. The thermal stability is studied by thermogravimetric analyser (TGA). The DC conductivity of the present samples is increased from 0.08 to 0.12 Scm −1 at 450 °C with Li 2 O doping. These materials can be used as electrolyte for battery/solid oxide fuel cell due to their good conductivity (~0.12 Scm −1 ) at 450 °C.