Development of Sr?FeTiO[?-Delta] electrode for solid oxide fuel cell

Abstract

Sr?FeTi?-x(Nb,V)xO? (x=0.05-0.50) double perovskites have been synthesized by the substitution of Nb and V on Ti sites of Sr?FeTiO? (SFT) and tested as electrode for intermediate temperature solid oxide fuel cell (IT-SOFC). The XRD analyses indicated Sr?FeTi?.??Nb?.??O? and Sr?FeTi?.??V?.??O? were pure and the impurities, Sr(FeNb) ?.?O? and Sr3(VO4) ?, were found with the increasing of Nb and V contents in SFT. By small addition of Nb and V in SFT, the electrical conductivity and electrochemical property of SFT was improved. Among the various oxide examined, Sr?FeTi?.??Nb?.??O? and Sr?FeTi?.??V?.??O? showed the highest electrical conductivity of 2.44 and 3.93 S cm??, respectively, and the lowest polarization resistance around 1.91 and 1.89 ? cm? at 800?C in air, respectively. For the application as electrode in SOFC, Sr?FeTi?.??Nb?.??O? and Sr?FeTi?.??V?.??O? showed a high potential to be used as both cathode and anode in electrolyte-supported single cell SOFC. The maximum power density of cathodes with LSGM electrolyte were achieved about 97 and 106 mW cm?? at 800?C for Sr?FeTi?.??Nb?.??O? and Sr?FeTi?.??V?.??O?, respectively. And the single cell performance of Sr?FeTi?.??Nb?.??O? and Sr?FeTi?.??V?.??O? anodes were 60 and 86 mW cm?? at 800?C, respectively. Furthermore, the reactivity tests demonstrated that Sr?FeTi?.??Nb?.??O? and Sr?FeTi?.??V?.??O? electrodes were chemically compatible with the LSGM electrolyte at 900?C for 5 hours in air.