Effect of Gd and Ti co-doping on electrical performance of Bi2O3 oxygen ion conductor

In this study, a new oxygen ion conductor electrolyte material with high conductivity was reported. Bi2O3 was co-doped with Gd2O3 and TiO2 by solid-phase synthesis method to obtain Bi1-3xGd2xTixO1.5+δ and Bi0.76Gd0.18-xTixO1.5+δ (TGSB) ceramics. The phase composition, surface morphology and electrical properties of TGSB samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and AC impedance respectively. XRD results show that only 6T12GSB has a single cubic fluorite structure, and impurity phases appear in other samples. The SEM results show that only when the doping concentrations of Gd and Ti are 12 mol.% and 6 mol.% respectively, the particle size is relatively smaller and there are no obvious pores. From the analysis of electrical properties, Gd dopant is helpful to the stability of the Bi2O3 phase than Ti dopant, but not beneficial to higher conductivity. When the doping concentration of Gd is higher than 16 mol.%, it becomes more stable. The conductivity of the 6T12GSB sample is relatively high. The conductivity of the TGSB samples is higher than that of the TLSB samples under the lower temperature condition (< 450 °C), and the electrical performance of Bi2O3-based materials are enhanced especially at low temperature.

Investigation of Ga Doping for Non-stoichiometric Sodium Bismuth Titanate Ceramics

The electrical performance of Ga3+ doping Na0.5Bi0.5TiO3-based oxygen ion conductor was studied. The Na0.52Bi0.47Ti1−xGaxO3−δ (x = 0, 0.01, 0.015, 0.02) samples were fabricated by the means of traditional solid-state reaction. The results of AC impedance measurement show that the bulk conductivity of Na0.52Bi0.47Ti1−xGaxO3−δ samples decrease monotonously with the increase of Ga3+ doping. At 673 K, the bulk conductivity of the Na0.52Bi0.47Ti0.98Ga0.02O3−δ sample is 7.19×10− 4 S/cm, which is lower than that of Na0.52Bi0.47TiO3−δ sample under the identical test temperature. The highest total conductivity emerges in the Na0.52Bi0.47Ti0.99Ga0.01O3−δ sample with 1.387×10− 4 S/cm at 623 K for the Ga3+ doping content of 1 mol%, which demonstrate that a slight of Ga3+ doping supports the enhancement of the total conductivity. A relaxation peak was observed in the Na0.52Bi0.47Ti1−xGaxO3−δ compounds. As the Ga3+ ions were introduced into the Na0.52Bi0.47TiO3−δ compound, there is an increasing trend of the relaxation activation energy educed by the internal friction test. In addition, the oxygen relaxtion height of Na0.52Bi0.47Ti1−xGaxO3−δ samples decreases along with the introduction of the Ga3+ doping, suggesting that the introduction of the Ga3+ leads to the decrease of mobile oxygen vacancy .

Mechanistic insight into oxygen vacancy migration in SrFeO3–δ from DFT+U simulations

SrFeO3–δ is known to be an effective oxygen ion conductor and oxygen vacancies are central to its performance. SrFeO3–δ displays four crystallographic structural transitions as it undergoes oxygen reduction over...

The Effect of Co-Doping at the A-Site on the Structure and Oxide Ion Conductivity in (Ba0.5−xSrx)La0.5InO3−δ: A Molecular Dynamics Study

A molecular dynamics simulation was used to investigate the structural and transport properties of a (Ba0.5−xSrx)La0.5InO3−δ (x = 0, 0.1, 0.2) oxygen ion conductor. Previous studies reported that the ionic conductivity of Ba-doped LaInO3 decreases because Ba dopant forms a narrow oxygen path in the lattice, which could hinder the diffusion of oxygen ions. In this study, we reveal the mechanism to improve ionic conductivity by Ba and Sr co-doping on an La site in LaInO3 perovskite oxide. The results show that the ionic conductivity of (Ba0.5−xSrx)La0.5InO3−δ increases with an increasing number of Sr ions because oxygen diffusion paths which contain Sr ions have a larger critical radius than those containing Ba ions. The radial distribution function (RDF) calculations show that the peak heights in compositions including Sr ions were lower and broadened, meaning that the oxygen ions moved easily into other oxygen sites.

The Effect of Co-Doping at the A-Site on the Structure and Oxide Ion Conductivity in (Ba0.5-xSrx)La0.5InO3-δ: A Molecular Dynamics Study

The molecular dynamics simulation has been used to investigate the structural and transport properties of (Ba0.5-xSrx)La0.5InO3-&delta; (x=0, 0.1, 0.2) oxygen-ion conductor. The previous studies reported that the ionic conductivity of Ba-doped LaInO3 decreases because Ba dopant forms narrow oxygen path in the lattice, which could hinder the diffusion of oxygen ion. In this study, we reveal the mechanism to improve the ionic conductivity by Ba and Sr co-doping on La site in LaInO3 perovskite oxide. The results show that the ionic conductivity of (Ba0.5-xSrx)La0.5InO3-&delta; increases with increasing numbers of Sr ions, which oxygen diffusion paths including Sr ion have larger critical radius than Ba ions. The RDF calculations showed the heights of peak in composition including Sr ions is lower and broaden, so oxygen ions moved easily into other oxygen sites.