Thermal stability study of SDC/Na 2CO 3 nanocomposite electrolyte for low-temperature SOFCs

Abstract

The novel core–shell nanostructured SDC/Na 2CO 3 composite has been demonstrated as a promising electrolyte material for low-temperature SOFCs. However, as a nanostructured material, stability might be doubted under elevated temperature due to their high surface energy. So in order to study the thermal stability of SDC/Na 2CO 3 nanocomposite, XRD, BET, SEM and TGA characterizations were carried on after annealing samples at various temperatures. Crystallite sizes, BET surface areas, and SEM results indicated that the SDC/Na 2CO 3 nanocomposite possesses better thermal stability on nanostructure than pure SDC till 700 °C. TGA analysis verified that Na 2CO 3 phase exists steadily in the SDC/Na 2CO 3 composite. The performance and durability of SOFCs based on SDC/Na 2CO 3 electrolyte were also investigated. The cell delivered a maximum power density of 0.78 W cm −2 at 550 °C and a steady output of about 0.62 W cm −2 over 12 h operation. The high performances together with notable thermal stability make the SDC/Na 2CO 3 nanocomposite as a potential electrolyte material for long-term SOFCs that operate at 500–600 °C.