Impact of electrical conductivity and the electrochemical performance of La₂NiO_4+δ and La₄Ni₃O_10±δ cathodes on symmetric cells for intermediate-temperature SOFCs

In the present work, the Ruddlesden-Popper (RP) phases La₂NiO_4+δ (La2) and La₄Ni₃O_10±δ (La4) were employed as cathode materials with Gd_0.1Ce_0.9O_2-δ (GDC) electrolyte for intermediate-temperature solid oxide fuel cells (IT-SOFCs). Cathode inks were deposited on the GDC substrate by the dip-coating technique. The electrochemical properties of the cathode in symmetric cells with GDC were investigated. The area-specific resistance (ASR) of the La₄Ni₃O_10±δ cathode is lower than that of the La₂NiO_4+δ cathode at 600, 700, and 800 ºC, with values of 6.91, 1.22, and 0.23 Ω cm², respectively. These values are better than other RP families previously reported. This work combines cathode layers to form multilayers as a La2La4La2 symmetric cell, enhancing the oxygen reduction reaction (ORR) properties, which exhibit an ASR value of 0.12 Ω cm² at 800 °C. We report a performance in a symmetric cell using a configuration with La2 and La4 cathodes that could be a promising alternative for IT-SOFCs.