Electrochemical property assessment of Sr-doped LaNi0.5Mn0.5O3-δ as cathode for intermediate-temperature solid oxide fuel cells

The perovskite oxides, La1-x.SrxNi0.5Mn0.5O3-delta,5 (LSNM, x = 0.0, 0.05, 0.1, and 0.15), have been evaluated as promising cathodes for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The polycrystalline LSNM nanoparticles are synthesized by a glycine-nitrate combustion method. The Rietveld refinements to X-ray diffraction patterns indicate that LaNi0.5Mn0.5O3-delta (LS0.0NM) is within the mixed Pbnm and R (3) over barc phases. However, the Sr-doping strategy initially makes the product only be R (3) over barc phase when x = 0.05, which is considered to be closely relevant to its high oxygen vacancy concentration. The R (3) over barc phase is also identified in x = 0.1 and 0.15 compounds. The electrochemical performance of LSNM has been performed by the electrochemical impedance spectra technique, and the La(0.9)Sr(0.1)iNi(0.5)Mn(0.5)O(3-delta) (LS0.1.NM) demonstrates the optimal electrochemical property as evidenced by the lowest area specific resistance (ASR) of 0.12 Omega cm(2) at 800 degrees C. Compared to the cobalt-containing cathode materials, the average thermal expansion coefficient (TEC) of LS0.1NM is about 11.33 x 10(-6) K-1, matching well with the prototypical electrolyte La0.9Sr0.1Ga0.8Mg0.2O3-delta,5 below 850 degrees C. The maximum power densities of the electrolyte support single cell with the configuration of LS0.1NM vertical bar LSGM vertical bar INiO-SDC reach 440 and 331 mW cm(-2) at 850 and 800 degrees C, respectively. Therefore, LS0.1NM could be considered as a novel potential cathode candidate for IT-SOFCs. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.