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Influence of La/Pr Ratio on the Ageing Properties of La 2-X Pr x NiO 4+δ as Cathodes in IT-SOFCs

2015; Institute of Physics; Volume: 68; Issue: 1 Linguagem: Inglês

10.1149/06801.0825ecst

2151-2051

Vaibhav Vibhu, Jean‐Marc Bassat, Aurélien Flura, Clément Nicollet, Jean‐Claude Grenier, Aline Rougier,

Ferroelectric and Piezoelectric Materials

The present study is focused on alternative oxygen electrodes for IT-SOFCs using Metal Supported Cells (MSCs) conditions. Ln 2 NiO 4+δ (Ln = La, Pr) compounds with the K 2 NiF 4 -type structure act as cathode materials for IT-SOFC due to their MIEC properties. Pr 2 NiO 4+δ (PNO) shows excellent electrochemical properties at intermediate temperature while La 2 NiO 4+δ (LNO) exhibits higher chemical stability. Thus, the properties of La 2 - x Pr x NiO 4+δ (LPNO) mixed nickelates were investigated with the aim to find the best compromise between chemical stability and electrochemical performances. Herein, the chemical stability of the nickelates under air at operating temperatures as well as the evolution of the polarization resistances, R p , during ageing ( i dc = 0 and i dc ≠ 0 conditions) were studied for duration up to one month. At i dc = 0 condition, the ageing of the half cells shows no change in R p . A different behavior is observed under i dc ≠ 0 conditions with an increase in R p in SOFC mode while interestingly, R p remains stable in SOEC mode.