New Gd-Zn co-doping enhanced mechanical properties of BaZrO_3 proton conductors with high conductivity for IT-SOFCs

摘要

We report here the synthesis and characterization of Gd-Zn co-doped BaZrO3 proton conducting oxides, developed for IT-SOFCs. BaZr0.8Gd0.2-xZnxO3-delta (BZGZn, x = 0, 0.02, 0.04, and 0.06) samples were prepared and then sintered at 1300-1500 degrees C for characterization of chemical stability, sinterability, mechanical properties, and proton conductivity. Gd-Zn co-doping significantly improved the mechanical performance of BaZrO3-based proton conductors: hardness and compressive strength increased, mainly resulting from improved relative density and the enhancement in grain boundary bonding strength. Importantly, Gd-Zn co-doping dramatically improved the total conductivity, which can achieved a higher conductivity of 2.54 x 10(-3) S.cm(-1) at 750 degrees C. A typical anode-supported single cell with Gd-Zn co-doped BaZrO3 electrolyte was tested using humidified hydrogen (similar to 3% H2O) as fuel, presenting a high maximum power density of 282 mW.cm(-2) at 700 degrees C. Preliminary results demonstrated that Gd-Zn co-doping is an effective way and has a great improvement in sinterability, mechanical properties and conductivity, leading to high electrochemical performance of IT-SOFC.