Segregation Induced Self-Assembly of Highly Active Perovskite for Rapid Oxygen Reduction Reaction

The development of high-performance electrochemical energy storage and conversion technologies hinges largely on the creation of highly efficient and durable electrode materials. For many promising perovskite-based electrode materials, however, nanosized islands of inert or insulating oxides, induced by cation segregation, are often formed on the surfaces under operating conditions, which severely degrade the electrocatalytic activity and long-term stability. Here, the findings in effectively mitigating the challenges by controlling localized surface chemical states via surface decoration are reported. It is found that addition of SrO at La0.6Sr0.4CoO3- surface can induce self-assembly of highly active perovskite coatings, avoiding the formation of inactive islands. Such coatings are found to act as active centers providing more than 10 times higher localized conductivity than the segregated islands and twice faster oxygen exchange kinetics than the perovskite surfaces, resulting in nearly 30 times improvement in electrochemical performances at 600 degrees C. The findings provide a novel approach to rational design and modification of perovskite electrode surfaces for higher and more durable electrochemical performance.