In this work, gallium is used as a dopant to stabilize Sr(CoFe)O3, developing a SrCo0.8Fe0.1Ga0.1O3-δ(SCFG) perovskite material to work as the electrodes of flexible SOFC and SOEC with a microtubular structure.
SCFG show a high oxygen reducing performance when it is prepared into oxygen separation membrane, Obtaining an oxygen flux of 3~6 mL·min-1·cm-2 at the temperature of 800~950°C. Even under pure CO2, pure CH4 and H2(4vol%), SCFG membrane still works steadily for as long as 200 h with no decreasing.
A microtubular solid oxide cell in the configuration of Ni-YSZ|YSZ|GDC|SCFG is fabricated and tested in SOFC or SOEC modes from 550 to 850°C, using hydrogen as the fuel or as the product, respectively. Under SOFC mode, a maximum power density of 1044 mW cm-2 is obtained at 750°C. In the electrolysis mode, when the applied voltage is controlled at 2V, the electrolysis current density reaches 3.33A cm-2 at 850°C with the hydrogen production rate up to 22.9 mL min-1 cm-2 (STP). These results reveal that SCFG is a very promising oxygen electrode material for the application in both SOFC and SOEC.