abstract
Understanding the processes of different cathode materials is part of the journey toward the development of intermediate-temperature solid oxide fuel cells. In this work, the onedimensional Ca3Co2O6 (C326) electrode and its composite with Ce0.9Gd0.1O2-d (CGO) are systematically investigated as a function of sintering temperature using a symmetrical cell test. For both batches of samples, the optimum sintering temperature is 1000 degrees C. Interpretation of the impedance spectra reveals that this optimization is associated with improvements in the processes of surface diffusion and interfacial charge transfer due to the higher effective reaction area for ionic transfer at the electrode/electrolyte interface and better connectivity between the electrode grains. The temperature dependence of the individual processes indicates that the addition of CGO significantly improves the steps of dissociative oxygen adsorption and diffusion, which should occur first on its surface, with the charge transfer of oxygen species at the CGO/C326 boundary being the rate-limiting step. (c) 2023 The Author(s). Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC. This is an open access article under the CC BY license (http://creativecommons.org/li
keywords
OXIDE FUEL-CELLS; ELECTROCHEMICAL PERFORMANCE; ELECTRODE-KINETICS; DOPED CERIA; TRANSPORT; LA2NIO4+DELTA; CONDUCTIVITY; DEGRADATION; COMPOSITE; MECHANISM
subject category
Chemistry; Electrochemistry; Energy & Fuels
authors
Melo, KPV; Araújo, AJM; Grilo, JPF; Fagg, DP; Macedo, DA; Loureiro, FJA
our authors
Francisco José Almeida Loureiro
Research Fellowship
João Grilo
Junior Researcheracknowledgements
This study was financed in part by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior-Brasil (CAPES) -Finance Code 001. Francisco J. A. Loureiro is thankful for the Investigator Grant CEECIND/02797/2020 from Fundacao para a Ciencia e a Tecnologia (FCT) . Daniel A. Macedo acknowledges the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq/Brazil, 309430/2019-4) . The authors also acknowledge the projects, PTDC/CTM-CTM/2156/2020, 2022.02498. PTDC, 2022.09319. PTDC, PTDC/QUI-ELT/3681/2020, POCI-01-0247-FEDER-039926, UIDB/00481/2020 and UIDP/00481/2020 from FCT, and CENTRO-01-0145-FEDER-181241 and CENTRO-01-0145-FEDER-022083 from Centro Portugal Regional Operational Programme (Centro 2020) , under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF) .