Preparation and electrochemical properties of SrCe 0·4 Zr 0·4 Yb 0·2 O 2·9 electrolyte

The perovskite Yb-doped strontium cerate–zirconate material, SrCe0·4Zr0·4Yb0·2O2·9, was prepared by solid-state reaction and the structure was characterized by X-ray diffraction. The calcination process of the powder was investigated by thermogravimetric/differential thermal analysis (TG–DTA). The high temperature conductivities were measured by d.c. four-probe technique in the temperature range from 500 to 950°C in wet hydrogen and effect of temperature on conductivity was investigated. The conductivity increased with the elevation of temperature from 500 to 950°C. The highest conductivity of 4·4 × 10 − 2 S· cm − 1 was observed for SrCe0·4Zr0·4Yb0·2O2·9 at 950°C. The current–voltage (I–V) and current–power (I–P) characteristics of the single cell (H2, Pt/SrCe0·4Zr0·4Yb0·2O2·9/Pt, O2) at temperature range from 600 to 850°C were tested. With the temperature increasing from 600 to 850°C, the open circuit voltage (OCV) decreased from 1·164 to 1·073 V and the ionic transfer number decreased from 0·996 to 0·946. At 850°C, the maximum power density of 25·2 mW· cm − 2 was observed.