A high-entropy perovskite cathode for solid oxide fuel cells

A new concept of high-entropy cathode is reported, which can bring about a definite improvement of electrochemical performance for solid oxide fuel cells (SOFCs). As a proof-of-concept, a new high-entropy perovskite oxide of La0.2Pr0.2Nd0.2Sm0.2Ba0.1Sr0.1Co0.2Fe0.6Ni0.1Cu0.1O3-δ (HEP) is successfully synthesized by a facile one-pot combustion method and proposed as a potential cathode for SOFC at intermediate temperatures. The high-entropy HEP formed a single phase of cubic perovskite structure and matched well with the adjacent electrolyte of Gd0.2Ce0.8O2-δ (GDC). The high-entropy HEP shows a sufficient electrical conductivity of 635.15 S·cm-1 at 800 °C. The high-entropy cathode of HEP achieved a much lower polarization resistance of 0.3 Ω·cm2 on YSZ electrolyte at 800 °C, which was only half of 0.6 Ω·cm2 for conventional La0.8Sr0.2FeO3-δ (LSF) cathode under same conditions. The YSZ-based SOFC with HEP cathode exhibited an outstanding output performance of 714.5 mW·cm-2 at 800 °C, indicating that the high-entropy perovskite as a new-type SOFC cathode is promising.