A high entropy stabilized perovskite oxide La0.2Pr0.2Sm0.2Gd0.2Sr0.2Co0.8Fe0.2O3-δ as a promising air electrode for reversible solid oxide cells

Reversible solid oxide cell (RSOC) is a new type of energy conversion device with significant applications, especially for power grid peaking advantage. However, the reversible conversion process of power generation/energy storage challenges the performance and stability of air electrodes. In this work, a novel high-entropy perovskite oxides La0.2Pr0.2Gd0.2Sm0.2Sr0.2Co0.8Fe0.2O3-δ (HE-LSCF) is proposed and investigated as an air electrode in RSOC. The electrochemical behavior of HE-LSCF was studied as an air electrode in both fuel cell and electrolysis modes. The polarization impedance (Rp) of the HE-LSCF electrode is only 0.25 Ω cm2 at 800 °C in an air atmosphere. At an electrolytic voltage of 2 V and a temperature of 800 °C, the current density reaches up to 1.68 A cm-2. The HE-LSCF air electrode exhibited excellent reversibility and stability, and its electrochemical performance remains stable after 100 h of reversible operation. With these advantages, HE-LSCF is shown to be an excellent air electrode for RSOC.