Growth of polycrystalline Pr₄Ni₃O₁₀ thin films for intermediate temperature solid oxide fuel cell cathode by radio frequency magnetron co-sputtering

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.