High-performance BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (BZCYYb) protonic ceramic fuel cell electrolytes by the Ba evaporation inhibition strategy

BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (BZCYYb) as a potential candidate for protonic ceramic fuel cells (PCFCs) electrolytes, often suffers from its high sintering temperature, making it deviate from the stoichiometric ratio and present a poor electrochemical performance than expected. Here, we reported a Ba evaporation inhibition strategy to fabricate stoichiometric BZCYYb electrolyte. By using this strategy, Ba evaporation and Y2O3/Yb2O3 segregation can be effectively suppressed. The electrolyte's average grain size is ∼5.29 μm, significantly promoting grain growth. An improvement of 60 % in total conductivity is accomplished at 700 °C in humid air, approaching 2.7 × 10−2 S cm−1. By constructing the proton transport model, the reasons for the enhanced electrochemical performance are explained from both bulk and grain boundary. Finally, at 700 °C, an anode-supported single cell with stoichiometric BZCYYb electrolyte demonstrates a maximum power density of 0.65 W cm−2, showing that the barium evaporation inhibition strategy is a powerful tool to fabricate PCFCs with high performance.