The Superior Properties of La0.6Ba0.4CoO3-δ Thin Film Electrodes for Oxygen Exchange in Comparison to La0.6Sr0.4CoO3-δ. Issue 6 (1st January 2016)

• Record Type: Journal Article
• Authors: Rupp, Ghislain M.; Schmid, Alexander; Nenning, Andreas; Fleig, Jürgen
• Is Part Of: Journal of the Electrochemical Society. Volume 163:Issue 6(2016)
• Page Start: F564
• Page End: F573
• Publication Date: 2016-01-01
• Subjects: cathode -- impedance -- LBC -- LSC -- oxygen surface exchange -- perovskite; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.1061606jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : The electrochemical properties of La0.6 Ba0.4 CoO3-δ (LBC) and La0.6 Sr0.4 CoO3-δ (LSC) dense thin film model electrodes, deposited by pulsed laser deposition at 600°C on yttria-stabilized zirconia (100) electrolytes, were investigated by electrochemical impedance spectroscopy (EIS) at 450–600°C and 10 −4 to 1 bar pO2 . This comparative study reveals the influence of the A-site dopant size on the catalytic activity for the oxygen exchange, chemical capacitance and electronic conductivity. For both thin films the overall oxygen reduction is still limited by the oxygen surface exchange, although an extraordinarily high activity for the oxygen reduction reaction (ORR) was measured (LBC ∼0.18 Ωcm²/LSC ∼0.6 Ωcm² at 604°C and 0.21 bar pO2 ). Moreover, LBC exhibits a rather low activation energy for the ORR (1.19 ± 0.11 eV) together with a high electronic conductivity (839 S·cm −1 at ∼442°C). Based on these excellent electrochemical properties, LBC may also be a highly promising material for porous cathodes in intermediate temperature (400–600°C) solid oxide fuel cells.