Electrolyte properties are significantly important for the long-term stability and performance ofmolten carbonate fuel cells (MCFCs). The Li/Na carbonate is considered an attractive electrolyte for MCFCs due to its high ionic conductivity and low volatility. However, low oxygen solubility is a serious drawback in Li/Na carbonate electrolytes, which hinders the oxygen reduction reaction (ORR) at theMCFC cathode. Several additives have been found to enhance the oxygen solubility in alkali carbonate electrolytes. In this study, the effect of Cs2CO3 in Li/Na and Li/K carbonate mixtures was investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The oxygen reduction activity improved with the increasing Cs concentration (1, 3, and 5 mol%) in all the studied carbonate melts. The addition of Cs2CO3 (5 mol%) to the Li/Na carbonate (68.0/32.0) resulted in an approximately 30% increase of the mass transfer parameter (C0 D0) of the dissolved oxygen species from 0.99 × 10-9 to 1.29 × 10-9 mol/cm2 s1/2 at 620°C. The changes in the ionic conductivity of the molten electrolytes with the Cs additive were also studied.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry