Promoting Influence of Doping Indium into BaCe _0.5 Zr _0.3 Y _0.2 O _3‐δ as Solid Proton Conductor

The influence of indium doping on chemical stability, sinterability, and electrical properties of BaCe _0.5 Zr _0.3 Y _0.2 O _3‐δ was investigated. The phase purity and the chemical stability of the powders in humid pure CO ₂ were evaluated by XRD . The dense electrolyte pellets were formed after the calcination at 1450°C for 8 h. SEM images and shrinkage plot showed that the sinterability of the samples was apparently improved by doping indium. The electrical conductivity was measured by impedance test through two‐point method, at both low (200–350°C) and high temperature ranges (450–850°C) in different atmospheres. BaCe _0.4 Zr _0.3 In _0.1 Y _0.2 O _3‐δ has been proved to be the optimal composition which simultaneously maximized the chemical stability, sinterability, and electrical conductivity which reached 1.1 × 10 ⁻² S/cm in wet hydrogen at 700°C, comparing with the 1.3 × 10 ⁻² S/cm for original BaCe _0.5 Zr _0.3 Y _0.2 O _3‐δ . Anode support fuel cell with a thin BaCe _0.4 Zr _0.3 In _0.1 Y _0.2 O _3‐δ electrolyte (15 μm) was fabricated by spin coating method. Maximum power density of 0.651 W/cm ² was obtained when operating at 700°C and fed by humid H ₂ (containing H ₂ O 3 vol%). The obtained fuel cell could efficiently run at 650°C for more than 100 h without any attenuation.