Charge and Mass Transfer on a La2O3 Added Li/Na or Li/K Molten Carbonate Meniscus Electrode of LaNiO3 Coated Au Ring for Oxygen Reduction Reaction

Abstract

LaNiO3 is an alternative cathode material of NiO for molten carbonate fuel cells (MCFCs) because of extremely higher stability than NiO in La saturated molten carbonates. In this study, the charge transfer on LaNiO3 and mass transfer resistance through La saturated molten carbonates for the ORR have been evaluated by the combination of a potential step method and steady state method on a meniscus electrode to discuss the ORR activity and mechanism of the LaNiO3 in Li/Na and Li/K carbonate eutectic with saturated La. The activity of ORR on LaNiO3 electrode was not less than that on NiO electrode and the rate-determination step would be competition of peroxide (POP) and percarbonate path (PCP) at meniscus state, and mass transfer resistance controlled over all reaction rate for steady state. In addition, Li/K system had higher ORR rate than Li/Na system because of large solubility of O2 under ambient pressure.