The structure and conductivity of new fluorite-type Bi2O3–Er2O3–PbO materials

The structural and conductivity evolution of fluorite-type Bi2O3–Er2O3–PbO solid electrolytes during long-term annealing

“…The partial airquenchable compositional domain of the fluorite-type phase is shown in [27]. Each quenched-in fluorite-type material was annealed in air in an alumina crucible at 500 and 600°C for up to 2000 h, followed by air quenching and grinding.…”

“…Examples include the ternary oxide systems Bi-Dy-W [15,16], Bi-Er-W [17], Bi-Ln-Te (Ln = La, Sm, Gd, Er) [18], Bi-Y-Nb [19], Bi-Ln-V (Ln = La-Yb) [20,21], Bi-La-U [22], Bi-Ca-Pb [23,24], Bi-Y-Pb [25] and Bi-Ln-Pb (Ln = La, Nd, Dy and Eu) [26]. We have recently reported a partial airquenchable domain of the fluorite-type phase in the Bi 2 O 3 -Er 2 O 3 -PbO system [27], and several of these fluorite-type materials displayed very high oxide-ion conductivity at 750°C. The high conductivity of Bi 2 O 3 -based materials is attributed to the Bi 3+ cation, with its 6s 2 lone pair electrons, being highly polarisable [28], and the highly disordered nature of the oxideion sublattice (occupancy and positional disorder) [27,[29][30][31][32][33][34][35][36].…”

“…Herein we describe the evolution of structure and conductivity for several quenched-in, fluorite-type materials recently reported in the Bi 2 O 3 -Er 2 O 3 -PbO system [27], during long-term annealing at 500 and 600°C, using a combination of techniques including powder XRD, neutron powder diffraction (NPD), SAED and DTA. We also describe the results of variable temperature conductivity experiments performed on quenchedin fluorite-type materials in the (BiO 1.5 ) 0.70 (ErO 1.5 ) 0.30−x (PbO) x series.…”

Electrical conductivity in the (Bi0.8-xLnxEr0.2)2O3 (Ln = La, Pr, Nd) systems

“…The degradation degree of (Bi0.7La0.1Er0.2)2O3 agreed with that of the (Bi0.7Gd0.3)2O3 system, because the average ionic radius of (La + 2Er)/3 was 0.1056 nm, which agreed with that of Gd (0.1053 nm). 13) In order to investigate the origin of the degradation, (Bi0.7Er0.3)2O3 was annealed at 773 K for the prolonged period of 600 h, resulting in occurring Er2O3 due to the phase separation, while the 300 h aged sample was not distinguishable by XRD (Fig. 7).…”

“…12) Recently, Webster et al 13) have also investigated the three component system, Bi2O3-Er2O3-PbO and found that some of these materials display high oxide ion conductivities, e.g. (BiO1.5)0.85(ErO1.5)0.12(PbO)0.03 showed the maximum conductivity of 0.72 S cm -1 at 973 K. Though it has been pointed out that the stabilized bismuth oxide has a weak resistivity for reduction atmosphere, 1),2) unfortunately, there has been a few data concerning the reduction properties of the bismuth oxide.…”