Preparation of a Gd_0.1Ce_0.9O_2-δ interlayer for intermediate-temperature solid oxide fuel cells by spray coating

Spray coating is widely used in industrial applications for the preparation of large, uniform thin films on various substrates due to its simplicity and cost-efficiency. To prevent reactions between a yttria-stabilised zirconia (YSZ) electrolyte and a La_0.6Sr_0.4Co_0.2Fe _0.8O_{3 - δ} (LSCF) cathode, a Gd_0.1Ce _0.9O_{2 - δ} (CGO) interlayer with a thickness of 2-3 μm is prepared on a YSZ electrolyte by spray coating. The results indicate that the properties of the CGO interlayer depend on its preparation conditions, including the powder pre-sintering temperature, the concentration of the dispersant and the sintering temperature. A densely packed CGO interlayer is obtained from a well-dispersed suspension of CGO powder pre-sintered at 750 °C with 6 wt.% PVP as a dispersant. After sintering at 1250 °C and 1300 °C, the CGO interlayer achieves an area special resistance (ASR) of 0.1 Ω cm² at 800 °C and 0.4 Ω cm² at 700 °C. Moreover, LSCF cells with a CGO interlayer obtain an average maximum power density greater than 600 mW cm^-2 at 750 °C. Obvious diffusion of Sr is not observed in the cells, indicating that the CGO interlayer prepared by spray coating effectively blocks Sr diffusion.