Associating and tuning sodium and oxygen mixed-ion conduction in niobium-based perovskites
Langue
en
Article de revue
Ce document a été publié dans
Advanced Functional Materials. 2020-03-10, vol. 30, n° 11, p. 1909254 (12 p.)
Wiley
Résumé en anglais
Pure ionic conductors as solid‐state electrolytes are of high interest in electrochemical energy storage and conversion devices. They systematically involve only one ion as the charge carrier. The association of two mobile ...Lire la suite >
Pure ionic conductors as solid‐state electrolytes are of high interest in electrochemical energy storage and conversion devices. They systematically involve only one ion as the charge carrier. The association of two mobile ionic species, one positively and the other negatively charged, in a specific network should strongly influence the total ion conduction. Nb5+‐ (4d0) and Ti4+‐based (3d0) derived‐perovskite frameworks containing Na+ and O2− as mobile species are investigated as mixed ion conductors by electrochemical impedance spectroscopy. The design of Na+ blocking layers via sandwiched pellet sintered by spark plasma sintering at high temperatures leads to quantified transport number of both ionic charge carriers tNa+ and tO2−. In the 350–700 °C temperature range, ionic conductivity can be tuned from major Na+ contribution (tNa+ = 88%) for NaNbO3 to pure O2− transport in NaNb0.9Ti0.1O2.95 phase. Such a Ti‐substitution is accompanied with a ≈100‐fold increase in the oxygen conductivity, approaching the best values for pure oxygen conductors in this temperature range. Besides the demonstration of tunable mixed ion conduction with quantifiable cationic and anionic contributions in a single solid‐state structure, a strategy is established from structural analysis to develop other architectures with improved mixed ionic conductivity.< Réduire
Mots clés en anglais
niobate perovskites
oxygen conductivity
sodium conductivity
mixed ion conduction
spark plasma sintering
Origine
Importé de halUnités de recherche