High performance praseodymium nickelate oxide cathode for low temperature solid oxide fuel cell

摘要

The praseodymium nickelate oxide Pr_1NiO_(4+δ), a mixed conducting oxide with the K_2NiF_4-type structure, was evaluated as cathode for low temperature solid oxide fuel cells (T= 873 K). The electrochemical performance of the cathode has been improved by optimization of the microstructure of the porous cathode combined with the use of a ceria barrier layer in between the cathode and zirconia electrolyte. Both low polarization and ohmic resistances were obtained using Pr_1NiO_(4+δ)-powders with a median particle size of 0.4 μm), and sintering the screen printed layer at a sintering temperature of about 1353 K for 1 h. These manufacturing conditions resulted in a cathode microstructure with well established connections between the cathode particles and good adhesion of the cathode on the electrolyte. Full-sized anode supported cells have been manufactured using the same process conditions for the Pr_1NiO_(4+δ) cathode and tested. The best results were obtained when using a dense Ce_(0.8)Gd_(0.2)O_(1.9) (20CGO) barrier layer. While a complete optimization of the cell preparation has not yet been achieved, the electrochemical performances of anode supported cells with Pr_1NiO_(4+δ) are higher than those with the well known state-of-the-art La_(0.6)Sr_(0.4)Fe_(0.8)Co_(0.2)O_(3-δ) (LSFC) material.