Cobalt-free perovskite Pr_0.5Sr_0.5Fe_1−xCu_xO_3−δ (PSFC) as a cathode material for intermediate temperature solid oxide fuel cells

PSFC (Pr_0.5Sr_0.5Fe_1−xCu_xO_3−δ) is a new perovskite-type oxide that has gained considerable attention as cathode material for intermediate temperature solid oxide fuel cells (IT-SOFCs), due to its high mixed ionic-electronic conductivity below 800 °C. In this work, PSFC (Pr_0.5Sr_0.5Fe_1−xCu_xO_3−δ, x = 0.2 and 0.4) powders were synthesized by the citrate method and structurally characterized by X-ray diffractometry. Screen-printed cathodes were sintered at 1050 °C and electrochemically characterized by impedance spectroscopy at 600–800 °C in pure oxygen. The area specific resistances (ASR) of the Pr_0.5Sr_0.5Fe_0.8Cu_0.2O_3−δ material are shown to be competitive with typical values reported for cobalt-based cathodes in the measured temperature range, while, importantly, offering a significantly lower activation energy, 0.62 eV. The thermal expansion coefficients of these Co-free cathodes are in the range of 13–15 × 10⁻⁶ °C⁻¹, in a temperature range 200–650 °C, demonstrating a good thermal compatibility with gadolinia doped ceria (CGO) electrolytes. - Highlights: • Cobalt-free Pr_0.5Sr_0.5Fe_1−xCu_xO_3−δ (PSFC) cathodes successfully prepared by the citrate method. • PSFC cathodes are thermally compatible with CGO electrolytes. • Pr_0.5Sr_0.5Fe_0.8Cu_0.2O_3−δ presents competitive area specific resistances of low activation energy, 0.62 eV.