The role of 8 mol % yttria stabilized zirconia in the improvement of electrochemical performance of lanthanum manganite composite electrodes

Journal Article · Mon Jun 01 04:00:00 EDT 1998 · Journal of the Electrochemical Society

DOI:https://doi.org/10.1149/1.1838578· OSTI ID:653348

Wang, S; Jiang, Y; Zhang, Y; Yan, J; Li, W ^[1]

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1. Chinese Academy of Sciences, Dalian (China). Dalian Inst. of Chemical Physics

In this study, 8 mol % yttria stabilized zirconia (YSZ) + La{sub 0.8}Sr{sub 0.2}MnO{sub 3} (LSM) composite electrodes with addition of various amounts of YSZ were prepared on YSZ plates by a screen-printing method. The electrodes were then examined by scanning electron microscopy (SEM) and studied by ac impedance, cyclic voltammetry, and potential step as well as a polarization technique. For the oxygen reduction reaction on the pure LSM electrode, the dissociative adsorption of oxygen on the LSM surface and the transfer of oxygen ions from the triple-phase boundary (TPB) to the YSZ electrolyte lattice were found to be two comparable rate-determining steps. The electrochemical resistance of the former step was proportional to the {minus}0.5 power of p{sub O{sub 2}}, with a high activation energy of {approximately}2.0 eV. The electrochemical resistance of the latter step was found to be independent of p{sub O{sub 2}} with a low activation energy of {approximately}1.0 eV. With addition of YSZ to the LSM electrode, the electrochemical activity was improved substantially with much lower electrochemical resistances for both steps. Furthermore, the dissociative adsorption of oxygen became less rate determining on the electrode with more YSZ addition. It was found that the transfer of oxygen ion was the only rate-determining step on the 40% YSZ + LSM electrode. The improvement in the electrochemical performance with addition of YSZ was found mainly due to the spatial enlargement of the TPB area, which increased the electrochemically active sites for the oxygen adsorption and charge-transfer reaction.

• Sponsoring Organization: USDOE
• OSTI ID: 653348
• Journal Information: Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 6 Vol. 145; ISSN 0013-4651; ISSN JESOAN
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
36 MATERIALS SCIENCE
CATHODES
ELECTRICAL PROPERTIES
LANTHANUM OXIDES
MANGANESE OXIDES
REDOX REACTIONS
SOLID ELECTROLYTE FUEL CELLS
YTTRIUM OXIDES
ZIRCONIUM OXIDES