abstract
Pure NiO or lithiated NiO with distinct Li/Ni atomic proportions (50/50-LN55 and 30/70-LN37) were tested as protective barrier layers (PBLs) to enhance the stability of LaCoO3(LC) electrodes in cells with composite electrolytes (CEs) consisting of Gd-doped ceria (CGO) and a eutectic mixture of Na and Li carbonates (NLCs). PBLs and LC layers were sequentially deposited by screen printing before firing at 700 degrees C and 550 degrees C, respectively, to yield symmetrical cells (LC|PBL|CE|PBL|LC). Electrochemical testing involved impedance spectroscopy measurements in air in the 500 degrees C to 650 degrees C range. Scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM/EDS) revealed that distinct PBLs possess uneven wetting tendency, with impact on the role of LC layers. The best electrode performance (0.55 omega cm(2)electrode area specific resistance at 550 degrees C in air) was observed using the LN37 PBL, stable throughout endurance tests up to 200 hours. Possible electrode mechanisms consistent with experimental evidence suggest an active role of the molten phase as an intermediate provider of O(2-)transport between the electrode and CGO.
keywords
OXYGEN REDUCTION; CO2 SEPARATION; ELECTROCHEMICAL-BEHAVIOR; COMPOSITE ELECTROLYTES; OXIDE; CELL; CONDUCTIVITY; TEMPERATURE; IMPROVEMENT; STABILITY
subject category
Energy & Fuels; Nuclear Science & Technology
authors
Jamale, A; Starykevich, M; Marques, FMB
our authors
Atul Prabhakar Jamale
Junior Researcher
Fernando Manuel Bico Marques
Full professor
Maksim Starykevich
Junior Researcheracknowledgements
Fundacao para a Ciencia e a Tecnologia, Grant/Award Number: POCI-01-0145FEDER-016654 - TDC/CTM - CER/6732/2