Probing the Electrochemical Performance of SrFe0.9Ti0.1O3−δ for the Symmetric Electrode in Solid Oxide Fuel Cells

Symmetric electrodes are critical for lowering manufacturing costs and commercializing solid oxide fuel cell (SOFC) technology. SrFeO3-derived electrode materials demonstrated considerable potential for symmetrical SOFCs. The present work comprehensively investigates the electrochemical performance of SrFe0.9Ti0.1O3−δ as symmetric electrodes. The powder is synthesized using the solid-state reaction method. Despite stabilizing the cubic perovskite phase, a significant oxygen deficiency within the lattice is determined. Upon testing the symmetrical half-cells at 800 °C, SrFe0.9Ti0.1O3−δ offers an extremely low initial area specific resistance (ASR) of 0.03 Ω·cm2 in O2 and 0.067 Ω·cm2 in 3%H2O/H2. Although the ASR remains unchanged in O2, it increases to 0.24 Ω·cm2 in 3%H2O/H2 after 100 h of thermal aging. Similar behavior is seen on redox cycling the half-cells. The ASR increase in reducing conditions is attributed to the microcracks generation. The electrolyte-supported symmetrical single cells deliver a maximum power density of 509 mW·cm–2 at 800 °C. This value declines to 409 mW·cm–2 on thermal aging for 100 h. A power density loss similar to 449 mW·cm–2 is seen on performing multiple redox cycles (at the anode side) at 800 °C. Interestingly, a slight increase in electrode polarization resistance is recorded during these tests, highlighting the stability of the SrFe0.9Ti0.1O3−δ electrode in the SOFC environment.