A high-performance cobalt-free Ruddlesden-Popper phase cathode La1.2Sr0.8Ni0.6Fe0.4O4+δ for low temperature proton-conducting solid oxide fuel cells

Ruddlesden-Popper typological (R-P type) layered material La2NiO4 is known for the excellent ionic conductivity and fast oxygen kinetics, but limited by its electronic conductivity as a single-phase cathode for low-temperature proton-conducting solid oxide fuel cells (LT H-SOFC). Cobalt-doping can improve the electro-catalytic capability, accompanied with an increased thermal expansion coefficient (TEC), which would lead to the delamination at the cathode/electrolyte interface. In this assignment, strontium and iron codoped R-P phase cathode La1.2Sr0.8Ni0.6Fe0.4O4+delta (LSNF), exhibiting fine oxygen conduction, sufficient electronic conductivity and compatible TEC ith the electrolyte, is investigated thoroughly. The single cell with LSNF cathode based on BaZr0.1Ce0.7Y0.2O3-delta (BZCY) electrolyte achieves a maximum power density (MPD) of 781 mW cm(-2) with the low interfacial polarization resistance (R-p) of 0.078 Omega cm(2) at 700 degrees C. Interestingly, the single cell can also possess an eximious power output of 138.5 mW cm(-2) at relatively low temperature of 500 degrees C. Moreover, the excellent long-term stability with no observable performance degradation for almost 100 h at 600 degrees C could also indicate that the single-phase R-P layered material LSNF is a preeminent cathode candidate for LT H-SOFC. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.