Oxygen ion conductivity in a new class of layered bismuth oxides

New Aurivillius-Related Phases in the Sb–(W,V)–O System: Structural Study and Properties

“…In that figure two straight lines are observed, being the E values 0.50$0.01 and 0.44$0.01 eV for the y"0.25 and x"0.25 samples, respectively. The activation energies found for both phases are close; however, these values are lower than those usually found for Aurivillius compounds in which conductivity is dominated by diffusion of oxide ions (30)(31)(32).…”

“…For temperatures below 140°C, besides the behavior described for and in the low-frequency region, two new dependencies of those parameters in the high-frequency region are observed: shows a dispersive regime, whereas seems to follow another linear dependence with lower slope. The high-frequency behavior of and is associated with ac conductivity, probably related to diffusion of oxygen vacancies (31)(32)(33)(34)(35)(36) according to the oxygen deficit of the [(W, V)-O] layers; however, the oxide ion conduction does not appreciably affect dc conductivity (low-frequency region) which is dominated by hopping electron conduction. This indicates that a portion of V is V(IV) in the y"0.25 sample despite the majority of V(V).…”

In situ X-ray diffraction studies of electroceramics

“…The BIMEVOX fast ion conductors represent the 1-layer variant and have been well characterized [31]. Early reports indicated that the 3-and 4-layer variants were also technologically important fast ion conductors [34][35][36][37][38]. In addition, the non-centrosymmetric 2-, 3-, etc.…”

“…Bi 2 Sr 2 Nb 2 TiO 12 is a centrosymmetric Aurivillius phase that crystallizes in space group 14/mmm and has been carefully characterized using both X-ray and neutron powder diffraction [51][52][53][54]. Thomas et al [38] and Kendall et al [34][35][36]50] suggested that full replacement of Ti by Ga or Al creates oxygen vacancies that fully disorder at approximately 775 • C.…”

Defect and dopant properties of the Aurivillius phase Bi4Ti3O12

“…1) has recently been shown to produce excellent fatigue-free performance compared to the parent composition [6]. Also, prior work has reported the presence of promising oxide ion conductivity in n ¼ 3 and 4 Aurivillius phases via doping with aliovalent cations, e.g., M 3+ (M=Al, Ga, In) for Ti 4+ [10]. The conductivity is proposed to occur via a conventional hopping mechanism, requiring oxygen vacancies in the structure.…”