Synthesis, characterization and electrochemical evaluation of high-performance Sr(Ce 0.6 Zr 0.4 ) 0.85 Y 0.15 O 3−δ /Sm 0.2 Ce 0.8 O 1.9 co-ionic conducting composite electrolytes for solid oxide fuel cells

The Sr(Ce 0.6 Zr 0.4 ) 0.85 Y 0.15 O 3−δ /Sm 0.2 Ce 0.8 O 1.9 (Strontium Cerium Zirconium Yttrium oxide [SCZY] and Samarium-doped Ceria [SDC]) co-ionic conducting composite electrolyte was successfully prepared by separately synthesising SCZY and SDC via the citrate-EDTA complexing method, followed by mechanical mixing through ball milling. After sintering at 1450 °C for 5 h, the composite exhibited a dense structure with retained integrity. Electrochemical and structural analyses were conducted under varied atmospheres and temperatures. The Pt/SCZY-SDC/Pt cell's total electrical conductivity and activation energy were determined using electrochemical impedance spectroscopy, yielding values of 0.039 S cm −1 and 61.56 kJ mol −1 , respectively, in H 2 /Air at 600–800 °C. Conductivity measurements indicated H + and O 2− ion conductivities of 0.228 and 0.00349 S cm −1 , respectively, at 800 °C. Notably, the electrolyte-supported Pt/SCZY-SDC/Pt cell demonstrated a power output of 21.7 mW cm −2 and an open-circuit voltage of 0.74 V at 800 °C, featuring a 1.19-mm electrolyte thickness and 2.54 cm 2 cathode area.