Mixed ionic-electronic conductivity, phase stability and electrochemical activity of Gd-substituted La2NiO4+delta as oxygen electrode material for solid oxide fuel/electrolysis cells


Ruddlesden-Popper La2-xGdxNiO4+delta (x = 0-0.4) nickelates were synthesized by glycerolnitrate combustion technique and explored as potential oxygen electrode materials for solid oxide fuel/electrolysis cells. Similar to the parent La2NiO4+delta, the metastability of RP-type n = 1 structure limits the applicability of La2-xGdxNiO4+delta to temperatures below 900 degrees C. These solid solutions are mixed conductors with predominantly p-type electronic conductivity that exceeds 50 S/cm at 500-800 degrees C in air. Substitution by gadolinium does not change the overstoichiometric oxygen content in air but has a negative impact on the mobility of interstitial oxygen, most likely, due to steric effects associated with the lattice shrinkage on doping. The electrochemical activity of bilayer electrodes comprising functional La2-xGdxNiO4+delta and current collecting LaNi0.6Fe0.4O3-delta + 3 wt% CuO layers in contact with Ce0.8Gd0.2O1.9 electrolyte was studied in air at 550-850 degrees C. Analysis of electrochemical impedance spectroscopy data employing the ALS (Adler-Lane-Steele) model revealed the limiting role of oxygen-ionic conductivity of functional La2-xGdxNiO4+delta materials in overall electrode performance. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.



subject category

Chemistry, Physical; Electrochemistry; Energy & Fuels


Pikalova, E; Kolchugin, A; Zakharchuk, K; Boiba, D; Tsvinkinberg, V; Filonova, E; Khrustov, A; Yaremchenko, A

our authors


Synthesis of the materials, XRD, BET and SEM study were performed using the equipment of the Shared Access Centre Composition of Compounds, IHTE UB RAS, with the support from the Government of the Russian Federation, Agreement No. 02.A03.21.0006 (Act 211) . The electrochemical studies were supported financially by the Russian Foundation for Basic Research (RFBR) , grant No. 200300151. K.Z., D.B. and A.Y. gratefully acknowledge financial support by the project CARBOSTEAM (POCI-01-0145-FEDER-032295) funded by FEDER through COMPETE2020 - Programa Operacional Competitividade e Internacionalizacao (POCI) and by national funds through FCT/MCTES, and by project CICECO - Aveiro Institute of Materials (UIDB/50011/2020 & UIDP/50011/2020) financed by national funds through the FCT/MCTES and when appropriate cofinanced by FEDER under the PT2020 Partnership Agreement. K.Z. acknowledges PhD scholarship by the FCT (SFRH/BD/138773/2018) .

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