Oxygen-Deficient Nd0.8Sr1.2Ni0.8M0.2O4-δ (M = Ni, Co, Fe) Nickelates as Oxygen Electrode Materials for SOFC/SOEC. (10th July 2019)

• Record Type: Journal Article
• Authors: Arias-Serrano, Blanca I.; Kravchenko, Ekaterina; Zakharchuk, Kiryl; Grins, Jekabs; Svensson, Gunnar; Pankov, Vladimir; Yaremchenko, Aleksey
• Is Part Of: ECS transactions. Volume 91:Number 1(2019)
• Page Start: 2387
• Page End: 2397
• Publication Date: 2019-07-10
• Subjects: Electrochemistry -- Periodicals; Electrochemistry; Periodicals; Electronic journals; Electronic journal; 541.37
• DOI: 10.1149/09101.2387ecst
• Languages: English
• ISSNs: 1938-5862

Abstract

Abstract : Ruddlesden-Popper Nd0.8 Sr1.2 Ni0.8 M0.2 O4-δ (M = Ni, Co, Fe) nickelates have been characterized as prospective oxygen electrode materials for solid electrolyte cells. XRD studies showed that these oxides retain tetragonal K2 NiF4 -type structure in air until at least 900°C. Average thermal expansion coefficients of Nd0.8 Sr1.2 Ni0.8 M0.2 O4-δ calculated from the structural data are in the range 14.5-15.8 ppm/K. TGA studies revealed that these nickelates are oxygen-deficient in air at temperature above 700°C but tends to oxygen stoichiometry or minor excess on cooling. Incorporation of cobalt or iron into nickel sublattice of Nd0.8 Sr1.2 NiO4-δ reduces oxygen deficiency and electrical conductivity. Electrochemical impedance spectroscopy studies of symmetrical cells showed that porous Nd0.8 Sr1.2 Ni0.8 M0.2 O4-δ electrodes applied onto Ce0.9 Gd0.1 O2-δ electrolyte exhibit quite similar performance, with lowest values of polarization resistance (0.8 Ω⸱cm 2 at 800°C) observed for M = Ni. The polarization resistance can be further decreased (down to 0.04 Ω⋅cm 2 at 800°C for M = Ni) by surface modification with PrO x .