High-Temperature Structural and Electrical Characterization of Reduced Oxygen-Deficient Ruddlesden-Popper Nickelates
authors Kravchenko, E; Neagu, A; Zakharchuk, K; Grins, J; Svensson, G; Pankov, V; Yaremchenko, AA
nationality International
journal EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
author keywords Layered compounds; Nonstoichiometric compounds; Mixed-valent compounds; Nickelates; Solid-state structures; Conducting materials
keywords OXIDE FUEL-CELLS; PEROVSKITE-TYPE OXIDES; ELECTROCHEMICAL PROPERTIES; CRYSTAL-CHEMISTRY; CATHODE MATERIALS; OXIDATION-STATE; MIXED-OXIDE; SOL-GEL; LA2-XSRXNIO4; DEFECT
abstract High-temperature characterization of oxygen-deficient Sr-rich (La1-xSrx)(2)NiO4-delta (x = 0.5-0.8) solid solutions under mildly reducing conditions with p(O-2) approximate to 5x10(-5) atm was performed by employing structural and thermal analysis, TEM, and electrical conductivity measurements. Oxygen losses from the crystal lattice on reduction were found to result in a reversible transition from the tetragonal (I4/mmm) to the orthorhombic (Immm) structure and shrinkage of the crystal lattice for the compositions with x > 0.5. TEM and thermogravimetric analysis evidenced slow kinetics of the structural transition. The increase in oxygen deficiency under reducing conditions is accompanied by localization of the electronic charge carriers, a drop of the p-type electronic conductivity, and a transition from metallic-like to semiconducting behavior. The extent of changes in oxygen nonstoichiometry, unit--cell dimensions, average Ni oxidation state, electron-hole concentration, and electronic conductivity on reduction is interrelated with the strontium content. The results suggest that the electrical conductivity of (La1-xSrx)(2)NiO4-delta ceramics depends mainly on the average Ni oxidation state.
publisher WILEY-V C H VERLAG GMBH
issn 1434-1948
year published 2018
issue 28
beginning page 3320
ending page 3329
digital object identifier (doi) 10.1002/ejic.201800091
web of science category Chemistry, Inorganic & Nuclear
subject category Chemistry
unique article identifier WOS:000440288700005
  ciceco authors
  impact metrics
journal analysis (jcr 2017):
journal impact factor 2.507
5 year journal impact factor 2.381
category normalized journal impact factor percentile 70.000
dimensions (citation analysis):
altmetrics (social interaction):



 


Apoio

1suponsers_list_ciceco.jpg