Reversible Solid Oxide Cells (R-SOCs) hold significant potential for renewable energy storage and utilization, but the application of traditional cobalt-based perovskite air electrode materials is limited due to their high thermal expansion coefficients and structural instability.

This study aims to design and fabricate novel high-efficiency air electrodes to improve the operational efficiency and stability of fuel cells.

Based on traditional double perovskite oxide PrBa_0.8Ca_0.2Co₂O_6-δ (PBCC), a novel B-site high-entropy perovskite oxide, i.e., PrBa_0.8Ca_0.2Fe_0.4Co_0.4Ni_0.4Cu_0.4Y_0.4O_6-δ (PBC-FCNCY), was proposed to achieve a substantial reduction in cobalt content via a multi-element doping strategy while preserving superior electrochemical performance. Subsequently, X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS) were employed to characterize the performance of PBC-FCNCY.

Characterization results confirm that the high-entropy structure optimizes the crystal structure and microstructure of the material. Electrochemical tests results show that PBC-FCNCY air electrode achieves a peak power density of 1 105 mW·cm^-2 in fuel cell mode and a current density of ?1 418 mA·cm^-2 at 1.3 V in electrolysis cell mode at 700 °C, both outperforming PBCC air electrode. Furthermore, it operates stably for over 110 h in fuel cell mode and over 85 h in fuel cell/electrolysis cell cycling mode.

The novel B-site high-entropy air electrode for R-SOCs proposed in this study has characteristics of enhanced activity and prolonged durability, demonstrating its practical application potential in R-SOCs.