Cobalt and ion based perovskite such as Sr(CoFe)O₃, Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ and La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δare considered as promising cathodes of SOFC or anodes of SOEC. However, cobalt and iron oxides are easily reacted with the gases such as H₂, CH₄, CO₂and water steam at high temperature, causing the perovskite structure to be easily decomposed. To stabilize the perovskite structure of the electrodes is a serious challenge for the fabrication of the long-life SOFC or SOEC.

In this work, gallium is used as a dopant to stabilize Sr(CoFe)O3, developing a SrCo_0.8Fe_0.1Ga_0.1O_3-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.