Chemical Compatibility and Electrochemical Performance between LaAlO3-Based Electrolyte and Selected Anode Materials

Powders of La0.90Sr0.10Al0.97Mg0.03O3-delta (LSAM) were synthesized by the glycine-nitrate process, and then sintered at 1500 degrees C for 5 h. Impedance spectroscopy at 900 degrees C in air revealed that the conductivity of LSAM was 1.11x10(-2) S.cm(-1). The chemical compatibility of LSAM with anode materials NiO-Ce0.9Gd0.1O1.95 (Ni-GDC), Sr0.88Y0.08TiO3 (SYT) and La0.75Sr0.25Cr0.5Mn0.5O3 (LSCM) was characterized by X-ray diffraction, scanning electron microscopy with energy-dispersive X-ray spectroscopy and AC impedance spectroscopy. The results indicated that SYT and LSCM had poor chemical compatibility with LSAM because Sr2+, Ti4+, Mn3+, and Cr3+ diffused readily into the LSAM lattice. The interdiffusion of cations between LSAM and Ni-GDC at 1300 degrees C was limited, implying excellent chemical compatibility. The electrochemical performance of symmetrical cells of the anode materials was measured under hydrogen atmosphere. The area-specific polarization resistance of Ni-GDC was 5.12 Omega.cm(2) at 800 degrees C. An open-circuit voltage of 0.925 V and a power density of 19.5 mW cm(-2) were obtained at 800 degrees C for a 550 mu m thick LSAM electrolyte-supported single cell (Ni-GDC/GDC/LSAM/GDC/La0.75Sr0.25FeO3).