The relationship between the local structure and oxide ionic conduction of Nd2NiO4+δ possessing the K2NiF4 structure was investigated. Various oxygen nonstoichiometry samples of Nd2NiO4+δ prepared with different annealing oxygen partial pressures were examined. The local structure related to oxide ionic conduction was determined by the Nd K-edge extended X-ray absorption fine structure. The oxide ionic conductivity and surface exchange coefficient were estimated using electronic conductivity relaxation methods. The activation energy for the oxide ionic conductivity was found to have a direct correlation to the surface exchange coefficient. The bottleneck size for oxide ion conduction was strongly correlated to the oxide ionic conduction of interstitial oxygen and the oxygen surface exchange rate.
- Extended x-ray absorption fine structure
- Local structure
- Oxide ion conduction