Characteristics of electrolyte-supported SOFC single cells using hexagonal perovskite Ba3MoNbO8.5 and Ba7Nb4MoO20 ceramics

Abstract

The characteristics of two solid oxide fuel cells (SOFCs) were compared using Ba3MoNbO8.5 and Ba7Nb4MoO20 sintered at 1100 and 1300 °C, respectively, as electrolytes. The electrolyte-supported SOFC single cells, Pt ǀ Sm0.2Ce0.8O1.9 ǀ electrolyte ǀ Sm0.2Ce0.8O1.9 ǀ Pt, with an electrolyte thickness of 1.0 mm were prepared. The resistivity of the bulk + grain boundary components of Ba3MoNbO8.5 and Ba7Nb4MoO20 were 2.25k and 212 Ω cm, respectively, at 600 °C, and their apparent activation energies for ion conduction were 122.3 and 72.8 kJ mol−1, respectively at 450–600 °C. When the I–V curves were evaluated at 450–600 °C with the introduction of 3% H2 (N2 balance) and air to the anode and cathode, respectively, the open circuit voltages and maximum power outputs at 600 °C were 0.95 V and 1.3 mW cm−2 for Ba3MoNbO8.5 and 0.97 V and 9.3 mW cm−2 for Ba7Nb4MoO20, respectively.