Structural, thermal and conductive properties of Bi4−xMxV2O11 (M = La, Gd; 0 ⩽ x ⩽ 0.4) compounds

Bi4−xMxV2O11 (M = La, Gd) was prepared by solid state reactions. The amount of La and Gd in the (Bi4−xMxV2O11) was varied in the range of (0 ⩽ x ⩽ 0.4). The addition of La and Gd to Bi4V2O11 electrolyte was found to stabilize the β crystalline phase for x ⩽ 0.3. In addition, the phase transition corresponding β- to γ-phases are evident in the ionic conductivity plots as well as in XRD, DSC profiles of x ⩾ 0.3 samples. The highest ionic conductivity was observed in Bi3.9La0.1V2O11 and Bi3.8Gd0.2V2O11 samples in the range of 10−3–10−4 S/cm for 700–500 °C. These results were supported by impedance spectroscopy, X-ray diffraction (XRD) and differential scanning calorimetry (DSC).