PdO-doped BaZr0.8Y0.2O3−δ electrolyte for intermediate-temperature protonic ceramic fuel cells

This paper explores the potential to design a “superprotonic conductor” for operation in the intermediate temperature (IT) range through a doping approach with a conventional proton conductor. This approach is validated scientifically, based on the enhanced macroscopic transport properties of the oxide ion conductor. This system consists of a BaZr0.8Y0.2O3−δ (BZY) proton conductor and a small amount of palladium oxide (PdO). The influence of the PdO on the sinter activity of the highly refractory BZY material is not significant, with low rates of grain growth under typical sintering conditions, even though the addition of some PdO favors the grain growth of BZY materials to some extent. The conductivity of PdO-modified BZY (BZPY) is higher than that of BZY in the IT range, in all atmospheres and at all temperatures. The conductivity of 3 mol.% PdO-modified BZPY was 8.60 × 10−3 S cm−1 at 600 °C in wet 5% H2. The electrical conductivity of BZPY increases systematically with increasing PdO content (0.5–3 mol.%) in all atmospheres investigated.