Synthesis and electrochemical characterization of porous cathode materials for intermediate temperature solid oxide fuel cells
type: CreativeWork
description: Electrochemical characteristics of the half-cells Ce0.8Gd0.2O1.9 | La0.6Sr0.4CoO3‑, Ce0.8Gd0.2O1.9 | Pr0.6Sr0.4CoO3‑ and Ce0.8Gd0.2O1.9 | Gd0.6Sr0.4CoO3- and single cells La0.6Sr0.4CoO3‑ | Ce0.8Gd0.2O1.9 | NiO + Ce0.9Gd0.1O2-δ, Pr0.6Sr0.4CoO3‑ | Ce0.8Gd0.2O1.9 | NiO + Ce0.9Gd0.1O2-δ and Gd0.6Sr0.4CoO3‑ | Ce0.8Gd0.2O1.9 | NiO + Ce0.9Gd0.1O2-δ have been studied using electrochemical methods (impedance spectroscopy, cyclic voltammetry and chronoamperometry) at various electrode potentials E and temperatures T. Systematic analysis of electrochemical results demonstrates that kinetics of oxygen electroreduction depends noticeably on porosity and chemical composition of the cathodes used. Detailed analysis of the impedance complex plane (Z’’,Z’) plots indicate that at T  773 K the mixed kinetics behavior prevails for most half-cells studied (i.e. slow mass transfer and charge transfer limiting steps have been established). At higher negative potentials and temperatures the processes tend toward purely charge transfer limited oxygen electroreduction mechanism (phase angle   –5). The values of total activation energy, calculated for various cathodes, decrease with increasing the cathode negative polarisation. In addition to the electron transfer process (reduction of oxygen), the mass transfer process of electrochemically active pieces inside micro-, mesoporous solid cathode material can probably be the rate- determining step in agreement with the fitting results of the Nyquist plots. Käesolevas töös uuriti süstemaatiliselt poolelementide Ce0.8Gd0.2O2-δ | La0.6Sr0.4CoO3‑, Ce0.8Gd0.2O2-δ | Pr0.6Sr0.4CoO3‑ ja Ce0.8Gd0.2O2-δ | Gd0.6Sr0.4CoO3- ja ühikrakkude La0.6Sr0.4CoO3‑ | Ce0.8Gd0.2O2-δ | NiO + Ce0.9Gd0.1O2-δ, Pr0.6Sr0.4CoO3‑ | Ce0.8Gd0.2O2-δ | NiO + Ce0.9Gd0.1O2-δ ja Gd0.6Sr0.4CoO3‑ | Ce0.8Gd0.2O2-δ | NiO + Ce0.9Gd0.1O2-δ omadusi elektrokeemiliste meetoditega (impedantsspektroskoopia, kronokulonomeetria, tsükliline voltamperomeetria).. Elektrokeemilised uu…
abstract: Electrochemical characteristics of the half-cells Ce0.8Gd0.2O1.9 | La0.6Sr0.4CoO3‑, Ce0.8Gd0.2O1.9 | Pr0.6Sr0.4CoO3‑ and Ce0.8Gd0.2O1.9 | Gd0.6Sr0.4CoO3- and single cells La0.6Sr0.4CoO3‑ | Ce0.8Gd0.2O1.9 | NiO + Ce0.9Gd0.1O2-δ, Pr0.6Sr0.4CoO3‑ | Ce0.8Gd0.2O1.9 | NiO + Ce0.9Gd0.1O2-δ and Gd0.6Sr0.4CoO3‑ | Ce0.8Gd0.2O1.9 | NiO + Ce0.9Gd0.1O2-δ have been studied using electrochemical methods (impedance spectroscopy, cyclic voltammetry and chronoamperometry) at various electrode potentials E and temperatures T. Systematic analysis of electrochemical results demonstrates that kinetics of oxygen electroreduction depends noticeably on porosity and chemical composition of the cathodes used. Detailed analysis of the impedance complex plane (Z’’,Z’) plots indicate that at T  773 K the mixed kinetics behavior prevails for most half-cells studied (i.e. slow mass transfer and charge transfer limiting steps have been established). At higher negative potentials and temperatures the processes tend toward purely charge transfer limited oxygen electroreduction mechanism (phase angle   –5). The values of total activation energy, calculated for various cathodes, decrease with increasing the cathode negative polarisation. In addition to the electron transfer process (reduction of oxygen), the mass transfer process of electrochemically active pieces inside micro-, mesoporous solid cathode material can probably be the rate- determining step in agreement with the fitting results of the Nyquist plots. Käesolevas töös uuriti süstemaatiliselt poolelementide Ce0.8Gd0.2O2-δ | La0.6Sr0.4CoO3‑, Ce0.8Gd0.2O2-δ | Pr0.6Sr0.4CoO3‑ ja Ce0.8Gd0.2O2-δ | Gd0.6Sr0.4CoO3- ja ühikrakkude La0.6Sr0.4CoO3‑ | Ce0.8Gd0.2O2-δ | NiO + Ce0.9Gd0.1O2-δ, Pr0.6Sr0.4CoO3‑ | Ce0.8Gd0.2O2-δ | NiO + Ce0.9Gd0.1O2-δ ja Gd0.6Sr0.4CoO3‑ | Ce0.8Gd0.2O2-δ | NiO + Ce0.9Gd0.1O2-δ omadusi elektrokeemiliste meetoditega (impedantsspektroskoopia, kronokulonomeetria, tsükliline voltamperomeetria).. Elektrokeemilised uu…
author: Kivi, Indrek
date published: 2009-05-26T11:10:13Z
date modified: 2026-07-24T06:23:56Z
provider: University of Tartu
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Tartu