Exceptionally High-Performance Reversible Solid Oxide Electrochemical Cells with Ultrathin and Defect-Free Sm_(0.075)Nd_(0.075)Ce_(0.85)O_(2-δ) Interlayers

摘要

Solid oxide electrochemical cells (SOCs) are promising energy conversionand storage systems owing to their high efficiency and low environmentalimpact. To lower operating temperatures, the state-of-the-art SOCs withhighly active cobaltite-based oxygen electrodes essentially require dopedceriainterlayers to avoid undesirable reactions with commercially availablezirconia electrolytes. However, the inherent cation interdiffusion betweenceria and zirconia materials at high temperatures (>1300 ℃) has retarded theconstruction of highly dense and stoichiometric ceria/zirconia bilayers. Thisstudy reports the fabrication of a highly conductive, ultra-thin (250 nm), anddefect-free Sm_(0.075)Nd_(0.075)Ce_(0.85)O_(2-δ) (SNDC) interlayer via readily processablegelatin-assisted deposition. The SOC with the gelatin-derived SNDC interlayerachieved exceptionally high electrochemical performances both in the fuel cell(≈3.34 W cm~(-2)) and electrolysis mode (≈2.1 A cm~(-2) at 1.3 V) at 750 ℃—oneof the best records for SOCs with similar configuration to date—along withexcellent long-term durability (1500 h). Mechanistic analysis reveals that theultra-thin and dense structure of the SNDC interlayer provides a faster routefor oxygen-ion conduction and more active sites for both oxygen reductionand oxygen evolution reactions at the oxygen electrode/electrolyte interface.The findings suggest that the thin and dense gelatin-derived SNDC interlayerhas great potential for use in high-performance reversible SOCs.