Tuesday, 31 May 2016
Exhibit Hall H (San Diego Convention Center)
Solid oxide fuel cells (SOFCs) have attracted widespread attention due to their high energy conversion efficiency and low emissions [1]. The main objective of current research on SOFC is to improve the performance of these devices while operating at Intermediate Temperatures (IT-SOFCs). Both the cathode composition [2] and the microstructural design of the electrode film play an important role in obtaining optimal performances [3, 4]. Porous microstructures with small particle size enhance the catalytic properties by improving the gas distribution and by enlarging the reactive surface area. In this work, architecturally designed La2-xPrxNiO4+δ films (with x=0.0, 0.5, 1 and 2) have been prepared for the first time by Electrostatic Spray Deposition (ESD) and screen printing (SP). The X-ray diffraction patterns confirm the formation of the pure orthorhombic La2-xPrxNiO4+δ phase in all cases. These novel cathodes consist of an original porous 3D tree-like microstructure sandwiched between a thin dense ESD layer at the electrolyte side and topped by a porous SP layer. The polarization resistance (Rpol) of these La2-xPrxNiO4+δ cathodes was found equal to 0.42, 0.21, 0.11 (Figure 1) and 0.07 W.cm2 at 600°C for x = 0, 0.5, 1 and 2, respectively. These values corresponding to this solid solution are the lowest ones available in the literature to the best of our knowledge. The chemical stability decreases by increasing the Pr content while the Rpol improves. LaPrNiO4+δ is chemically stable up to 30 days at 700°C in air. To conclude, among the La2-xPrxNiO4+δ (0 ≤ x ≤ 2) solid solution, LaPrNiO4+δ shows the best compromise between electrochemical and chemical stability.
Figure 1: Nyquist plot for LaPrNiO4+δ at 600°C in air.
References
[1] D. Ding, X. Li, S. Y. Lai, K. Gerdes, M. Liu, Energy Environ. Sci., 2014, (7), 552.
[2] V. Vibhu, A. Rougier, C. Nicollet, A. Flura, J.C. Grenier, J.M. Bassat, Solid State Ionics, 2015, (278), 32.
[3] D. Marinha, L. Dessemond, E. Djurado, J. Power Sources, 2012, (197), 80.
[4] R. K. Sharma, M. Burriel E. Djurado, J. Mater. Chem. A, 2015, (3), 23833.