A high-performance reversible protonic ceramic electrochemical cell based on a novel Sm-doped BaCe0·7Zr0·1Y0·2O3-δ electrolyte

The present work describes a doping strategy to improve the electrochemical performance of BaCe(Zr)O3-based reversible protonic ceramic electrochemical cells (RePCECs). BaCe0.7Zr0.1Y0.2-xSmxO3-δ (0 ≤ x ≤ 0.2) synthesized by a solid-state reactive sintering method. Enhanced sintering with Sm-doping is observed with a significant increase of grain size as compared to un-doped samples. The improvement of the proton conductivity by proper Sm-doping is also achieved. This work fabricates and tests an electrochemical cell with a 25 μm thick electrolyte in both protonic ceramic fuel cell (PCFC) and protonic ceramic electrolysis cell (PCEC) operation modes. At the intermediate temperature of 600 °C, a maximum power density of 410 mWcm−2 is observed in PCFC mode under Air/H2 gradient, while a current density of 370 mAcm−2 is obtained with an applied voltage of 1.3 V in PCEC mode using 12 vol% H2O humidified air as feed gas and 5% H2 as sweep gas.