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Oxide ion conductivity in doped NdAlO[sub 3] perovskite-type oxides

Journal Article · · Journal of the Electrochemical Society; (United States)
DOI:https://doi.org/10.1149/1.2059351· OSTI ID:6587890
; ;  [1]
  1. Oita Univ. (Japan). Dept. of Applied Chemistry

Oxide ion conductivity in doped NdAlO[sub 3] Perovskite-type oxides was investigated. Among the alkaline earth cations the addition of Ca for Nd site is effective for increasing the oxide ion conductivity of NdAlO[sub 3]. Oxide ion conductivity increased anomalously with increases in the amount of Ca, and attained the maximum at x = 0.1 in Nd[sub 1[minus]x]Ca[sub x]AlO[sub 3], since the limit of the solid solution of Ca into the Nd site seems to be around x = 0.1. The addition of the cations for the Al site of Nd[sub 0.9]Ca[sub 0.1]AlO[sub 3] was also effective for increasing the oxide ion conductivity, and it was found that the substitution of Ga on Al sites is effective for enhancing the oxide ion conductivity of Nd[sub 0.9]Ca[sub 0.1]AlO[sub 3]. The oxide ion conductivity increased with increasing the Ga content and the highest oxide ion conductivity was attained at x = 0.5 in Nd[sub 0.9]Ca[sub 0.1]Al[sub 1[minus]x]Ga[sub x]O[sub 3]. Since the increased oxygen ion conductivity by doping Ga suppressed the p-type semiconduction in high oxygen partial pressure range, electrical conductivity was almost independent of the oxygen partial pressure. The theoretical electromotive forces were obtained from the galvanic cell measurement where Nd[sub 0.9]Ca[sub 0.1]Al[sub 0.5]Ga[sub 0.5]O[sub 3] was used as the electrolyte. Furthermore, the fuel cell where Nd[sub 0.9]Ca[sub 0.1]Al[sub 0.5]Ga[sub 0.5]O[sub 3], Ni, and La[sub 0.6]Sr[sub 0.4]MnO[sub 3] were used as electrolyte, anode, and cathode, respectively, exhibited the short-circuit current density higher than 400 mA/cm[sup 2] at 1273 K, when humidified H[sub 2] and O[sub 2] were used as fuels and oxidizing agent, respectively. These results suggest that the perovskite-type oxide, Nd[sub 0.9]Ca[sub 0.1]Al[sub 0.5]Ga[sub 0.5]O[sub 3], exhibits almost a pure oxide ion conductivity with high electrical conductivity over a wide range of oxygen partial pressures and temperatures.

OSTI ID:
6587890
Journal Information:
Journal of the Electrochemical Society; (United States), Journal Name: Journal of the Electrochemical Society; (United States) Vol. 141:12; ISSN 0013-4651; ISSN JESOAN
Country of Publication:
United States
Language:
English