Effect of Sr Deficiency on Electrical Conductivity of Yb-Doped Strontium Zirconate

Abstract

The effect of Sr-deficiency on microstructure, phase composition and electrical conductivity of SrxZr0.95Yb0.05O3-δ (x = 0.94–1.00) was investigated via X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy and impedance spectroscopy. The samples were synthesized by a chemical solution method and sintered at 1600 °C. According to X-ray diffraction data, the samples with x = 0.96–1.00 were single-phase oxides possessing an orthorhombic perovskite-type structure; while zirconia-based minor phases arouse at x = 0.94, which was confirmed by the electron microscopy. Sr stoichiometry was shown to influence the electrical conductivity. The highest total and bulk conductivities, 6–10−4 Scm−1 and 3–10−3 Scm−1, respectively, at 600 °C in humid air (pH2O = 3.2 kPa), were observed for the x = 0.98 composition. In the temperature range of 300–600 °C, the conductivity of the samples with x = 0.96–1.00 increased with the increase in humidity, which indicates a significant contribution of protonic defects to the charge transport. Electrical conductivity of SrxZr0.95Yb0.05O3-δ was discussed in terms of the defect formation model and the secondary phases precipitation.

Crystallographic, Structural, and Electrical Properties of W6+ Substituted with Mo6+ in Crystalline Phases such as TTB Structure

“…Ionic conduction, which is caused by movement of charge carriers, can account for this increase in conductivity at high temperatures and low frequencies [64]. The charge carriers' inability to adhere to excitation of the electric field at high frequencies accounts for conductivity's diminishing tendency at these frequencies [65].…”

Effect of Sn doping on sinterability and electrical conductivity of strontium hafnate

“…In addition, doping is a common approach to improving the sinterability of solid oxides. Solid oxide electrolytes, including those with a perovskite structure, are refractory materials, which are sintered at very high temperatures [28][29][30][31][32][33][34].…”

“…The powders of Sr0.995Ce0.005HfO3 and Sr0.995Ce0.005Hf0.995Al0.005O3 were synthesized by the solid state method, pressed into pellets and sintered at 1800 °C for 20 h in vacuum; it was found that the addition of Al re-sulted in the increase in density up to 98.9%. The use of spark plasma sintering (SPS) method was reported to be effective for fabrication of the high-density ceramics of strontium hafnate [30,31]. The powder synthesized by the solid state method was poured into a graphite die, placed in a SPS chamber, stepwise heated to a high temperature (1600-1900 °C), and kept at this temperature for 45 min; the relative density of the obtained samples was more than 99%.…”

Effect of Lu-Doping on Electrical Properties of Strontium Zirconate

“…SrZrO 3 -based perovskites are recognized as promising membranes for proton-conducting electrochemical devices because they combine appreciable proton conductivity with excellent chemical stability [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. Oxide-ion conductivity in solid oxides is realized due to the presence of oxygen vacancies in the structure.…”

“…SrZrO 3 doped with 5 mol.% Gd demonstrated an appreciable proton conductivity [ 16 ]. Substitution of Zr for Yb and Dy also resulted in an increase in the conductivity of SrZrO 3 [ 17 , 18 ]. Doping with 5 mol.% Yb and Y was revealed to result in a larger gain in conductivity compared to the same concentrations of In, Al and Ga [ 12 ].…”