Growth of polycrystalline Pr4Ni3O10 thin films for intermediate temperature solid oxide fuel cell cathode by radio frequency magnetron co-sputtering
Résumé
The performances of Solid Oxide Fuel Cells (SOFC) are strongly related to the catalytic/conductive properties of cathode materials, which are temperature dependent. The optimal temperature in operating conditions implies a tradeoff between high efficiency at high temperatures and improved lifetime at Intermediate Temperatures (IT). Among the candidates, Pr2NiO4 presents attractive functional properties but is susceptible to decompose into Pr4Ni3O10 under IT-SOFC conditions. In this contribution, a deposition process to obtain Pr4Ni3O10 phase were directly targeted as a potential alternative to the integration of Pr2NiO4 in IT-SOFC. Pr4Ni3O10 thin films have been deposited on Y-stabilized Zirconia substrates through a two-step process: (i) room temperature co-sputtering of metallic Ni and Pr targets, (ii) ex-situ annealing under O2 flux. The composition of thin films were adjusted by changing the power applied to each target and confirmed by Energy Dispersive Spectroscopy. X-Ray Diffraction analyses as a function of temperature were made to identify the temperature window to stabilize the desired phase. The structural and morphological features of polycrystalline Pr4Ni3O10 thin films were analyzed by Transmission Electron Microscopy and Scanning Electron Microscopy. Electrical resistivity of ~6.5.10−3 Ω cm and Seebeck coefficient of ~ – 23 μV K−1 at 150 °C highlight the synthesis of Pr4Ni3O10 continuous coatings representing a promising candidate for cathodes in IT-SOFC.
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