- Study of Structural, Thermodynamic and Electrical Properties of the BaCe0.4Zr0.4Pr0.2O3 (BCZP) Perovskite for Electrochemical Applications

BASBUS, JUAN F.; ARCE, MAURICIO D.; PRADO, FERNANDO; TROIANI, HORACIO E.; SERQUIS, ADRIANA; MOGNI, LILIANA V.

PyeongChang

Conferencia; 22nd International Conference on Solid State Ionics (SSI-22); 2019

Solid State Ionics

Barium cerates and zirconates Ba(Ce,Zr,M)O3−δ (M = Y+3, Sm+3, Gd+3) are oxides capable to transport protons through their crystal lattice by proton hopping between oxygen sites [1]. This feature makes them potential candidates as hydrogen sensors, membranes for hydrogen purification and isotopic exchange of hydrogen/deuterium/tritium (H/D/T), and electrolyte for Proton Conducting Solid Oxide Fuel Cell (PC-SOFC) and Solid Oxide Electrolyzer Cell (PC-SOEC). It was reported that Pr-doping on these family compounds decreases sintering temperature and introduces Mixed Ionic Electronic Conductivity (MIEC) [2][3]. Therefore, they are proposed as cathode for PC-SOFC instead of electrolyte. This work shows systematic study of BaCe0.4Zr0.4Pr0.2O3−δ (BCZP) perovskite as potential MIEC cathode to PC-SOFC. BCZP was synthesized by Solid State Reaction and sintered at 1600 °C for 12 hours. Crystal structure was studied by X-Ray Diffraction (XRD). Morphology and porosity were determined by Scanning Electron Microscopy (SEM). Crystalline structure and thermal expansion were characterized under O2-containing atmosphere by High Temperature X-Ray Diffraction (HT-XRD) and Dilatometry, respectively. Oxygen non-stoichiometry and chemical stability under CO2-rich atmosphere were evaluated by Thermogravimetry (TG). Electrical conductivity was characterized by Electrochemical Impedance Spectroscopy (EIS) and Two Probe Method (TPM) under O2-containing atmosphere with water vapor (~2 % H2O) and heavy water vapor (~2 % D2O). Protonic conductivity would be dominant mechanism below to 400 °C while above this temperature electron-hole conductivity would be dominant. BCZP presents potential applications as MIEC cathode for PC-SOFC between 400 and 600 °C.