Designing high-performance quasi-symmetrical solid oxide cells with a facile chemical modification strategy for Sr2Fe2−xWxO6−δ ferrites electrodes with in situ exsolution of nanoparticles
Kun Zheng, Jakub Lach, Paweł Czaja, Michał Gogacz, Patryk Czach, Agnieszka Brzoza-Kos, Piotr Winiarz, Jie Luo
Abstract
The chemical modification of perovskites is one of the most effective design strategies for electrode materials for solid oxide cells. In this work, the tungsten doping in Sr2Fe2−xWxO6−δ shows a significant impact on their physicochemical properties, and it leads to a substantial change of electrochemical properties in the air and reducing conditions, with Sr2Fe1.8W0.2O6−δ (Rp = 0.06 Ω cm2 at 800 °C stable for 100 h in air) and Sr2Fe1.6W0.4O6−δ (Rp = 0.56 Ω cm2 at 800 °C over 100 h in 5 vol% H2/Ar) being the best air and fuel electrode candidates, respectively. We have proposed an attractive design of high-performance quasi-symmetrical solid oxide cells with 80%Sr2Fe1.8W0.2O6−δ+20%GDC | LSGM | 80%Sr2Fe1.6W0.4O6−δ+20%GDC, demonstrating excellent power outputs (874 mW cm−2 at 850 °C in wet H2) and good current density of 743 mA cm−2 at 1.5 V in electrolysis mode at 750 °C. A good performance of 451 mW cm−2 was also recorded in wet CH4 at 800 °C. The in situ exsolved metallic iron nanoparticles decorated on the Sr2Fe1.6W0.4O6−δ anode contribute to the excellent electrochemical performance of cells. This study provides a successful scenario for designing high-performance symmetrical solid oxide cells with a facile chemical modification strategy for ferrites electrodes with in situ exsolution of nanoparticles.