Structural design/doping strategy is an efficient method to prepare electrolytes with high oxygen ionic conductivity, but there is still hindrance for solid oxide fuel cell (SOFC) commercialization. Recent advances in semiconductor ionic materials have developed a novel strategy in designing low-temperature electrolyte materials. Here, a heterostructure composite of LSFC (La0.6Sr0.4Fe0.8Cu0.2O3-δ) and SDC (Sm0.2Ce0.8O2−δ) is developed. The LSFC-SDC composite exhibits a high ionic conductivity, >0.1S/cm at 550 °C. With symmetrical NCAL (Ni0.8Co0.15Al0.05LiO2-δ)-coated electrode, cells with SDC-LSFC electrolyte exhibit high open-circuit voltage (OCV), and achieve a significant power improvement (>1000 mW/cm2) compared with pure SDC electrolyte at 550 °C. The short-term stability result has proven the operating ability of SDC-LSFC electrolyte under fuel cell environment (H2/air). This work demonstrates a new developing route of low-temperature solid oxide fuel cell (LTSOFC), which is different from the conventional SOFC.
