La1.6Sr0.4NiO4 one-dimensional nanofibers as cathode for solid oxide fuel cells
Résumé
La1.6Sr0.4NiO4 (LSN) nanofibers are prepared by electrospinning technique and used as cathode materials for solid oxide fuel cells (SOFCs) with Ce0.9Gd0.1O1.95 (CGO) as electrolyte. The as-prepared cathode is highly porous but forms a good contact with the CGO electrolyte after rapid sintering at 900 °C for 15 min in air. The electrode performance of LSN nanofibers is measured at various temperatures and under different oxygen partial pressures. Two main oxygen reduction reaction (ORR) processes are identified. The rate limiting step for the ORR is the charge transfer process. The LSN nanofiber cathode exhibits a polarization resistance (Rp) of 0.40 Ω cm2 at 700 °C in air, 0.80 Ω cm2 at 650 °C and 1.59 Ω cm2 at 600 °C. These results demonstrate that the LSN nanofiber architecture significantly enhances the electrochemical activity of these cathodes for the ORR compared to usual porous electrodes, which points out the interest of such a synthesis technique for preparing SOFCs cathode materials with peculiar morphology.