Exploring the impact of structural modification of double perovskite composite cathode material on oxygen reduction reaction in intermediate temperature solid oxide fuel cell

The electrochemical performance of double perovskite oxides as cathode material for intermediate-temperature solid oxide fuel cells can be enhanced through structural modifications. The electrochemical performance of Sr₂CoNbO_6-δ-Sm_0.2Ce_0.8O_2-δ (SCNO-SDC) composite structurally assembled using various techniques, one-pot, electrospinning, and mixing have been studied to understand the structural change and performance relationship. The nanofiber composite exhibited superior cell performance of 0.996 W/cm² peak power density and 0.079 Ω cm² polarisation resistance compared to one-pot and the mixed composite, which yielded 0.831 W/cm² and 0.0908 Ω cm², and 0.706 W/cm² and 0.206 Ω cm², respectively, at a temperature of 700°C. The work emphasises a successful approach to modifying the structure of the SCNO-SDC cathode by identifying the rate-determining process to produce superior electrode materials. The improved electrochemical performance of the structurally modified cathode composite is a result of its cohesive interfacial interaction, which significantly improves the kinetics of the electrode reaction and stability.