Lifetime Expectancy of molten carbonate fuel cells: Part I. Effect of temperature on the voltage and electrolyte reduction rates

Abstract

Electrolyte depletion is a significant setback in the operation of molten carbonate fuel cells (MCFCs). The electrolyte loss mostly occurs as a result of the high operating temperatures of over 873 K. The effect of temperature on MCFCs was studied using several 7 cm2 coin-type MCFCs operated at 873, 973 and 1073 K. Lithium-potassium carbonate (Li/K) was used as an electrolyte in this study. A decrease in cell performance with time was observed at all temperatures. The performance degradation was found to be more severe at 1073 K than at 973 K and 873 K. The electrolyte loss rate was observed by chemical means to have increased with increasing temperature. A more severe electrolyte loss rate was observed in cells operated at 1073 K, such that the electrolyte amount reduced by half after 250 h of cell operation. In this research work, a factor, FWV, which correlates the electrolyte loss rate, voltage reduction rate, and cell life, is introduced. Its dependence on the cell electrode area and operating temperature make it a suitable parameter for simulating MCFC's lifetime.