Tantalum doped La0.6Sr0.4FeO3−δ electrodes for symmetrical proton conducting solid oxide fuel cells

Abstract

Symmetrical solid oxide fuel cells (SSOFCs) possessing the same electrodes have attracted plenty of scientific interest for lots of advantages compared with conventional SOFCs with different anodes and cathodes. In this paper, a 10 mol% Ta doped perovskite-type oxide La_0.6Sr_0.4FeO_3−δ, named La_0.6Sr_0.4Fe_0.9Ta_0.1O_3−δ (LSFT), is studied as both an anode and cathode for proton conducting SOFCs (H-SOFCs) operated between 500 and 800 °C. LSFT is chemically compatible with a BaZr_0.1Ce_0.7Y_0.1Yb_0.1O_3−δ (BZCYYb) electrolyte, even co-sintering at 1000 °C for 10 h. The activating energy (E_a) of electrical conductivity for LSFT is only 0.44 eV. At 800 °C, the polarization resistances (R_ps) for LSFT barely reach 0.02 Ω cm² in air and 0.1 Ω cm² in H₂, and the corresponding E_a values are only 1.39 and 0.91 eV, respectively. The peak power density (PPD) of a symmetrical H-SOFC (SHSOFC) using LSFT electrodes is 0.697 W cm⁻² at 800 °C. Herein, LSFT should be a promising electrode for SHSOFCs.