Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5146836 | International Journal of Hydrogen Energy | 2017 | 13 Pages |
Abstract
In view of utilization as cathodes for intermediate temperature solid oxide fuel cells (SOFCs), the La2âxSrxNiO4±δ (x = 0.2 and 0.8, δ > 0) series of compounds were evaluated with respect to their electrical conducting, thermomechanical and electrochemical properties. On the one hand, La1.2Sr0.8NiO4âδ exhibits a higher electrical conductivity (>180 S cmâ1 in the temperature range 600-800 °C) and a lower electrode polarization under open-circuit voltage conditions (â¼0.12 Ω cm2 at 800 °C) than La1.8Sr0.2NiO4+δ, together with a suitable thermal expansion coefficient (13.8 Ã 10â6 Kâ1 averaged between 50 and 1000 °C). On the other hand, the structure and electrochemical properties of La1.2Sr0.8NiO4âδ electrode were obviously changed after being subjected to cathodic polarization. The cathodically polarized La1.2Sr0.8NiO4âδ electrode showed an aggregation of strontium oxide onto the surface, concomitant with a degradation of electrochemical properties. By contrast, the structure and electrochemical properties of La1.8Sr0.2NiO4+δ electrode before and after cathodic polarization were basically unvaried. The disparate changes in structure and electrochemical properties of the two electrodes were interpreted in terms of their differing peculiarities in oxygen nonstoichiometry. The results of this work highlight the importance of strontium content and thereby oxygen nonstoichiometry of La1âxSrxNiO4±δ electrodes to their structural stability under cathodic polarization conditions, which is a critical point to be used as cathodes in SOFCs.
Related Topics
Physical Sciences and Engineering
Chemistry
Electrochemistry
Authors
Ya-Ping Wang, Qing Xu, Duan-Ping Huang, Kai Zhao, Min Chen, Bok-Hee Kim,