The influence of low operating temperature on molten carbonate fuel cells decay processes

As a key step towards the development of a prototype of a 1 kW phosphoric acid fuel cell at the CNR-TAE Institute, the first made in Europe based on an 'in-house' know- how, tests in a subscale monocell station have been performed. The main objective of these studies was to establish the optimum operating conditions as well as to determine the effects of ageing on the cell performance. Prolonged tests totalling more than 40 000 h operations in a monocell have provided useful information to select and scale up the range of optimal operating conditions for the 1-kW stack. This paper illustrates the main findings for phosphoric acid management, humidifier temperature of gases and cell working current density. The endurance tests indicated that the most predominant mechanism of decay is the PTFE--carbon electrostatic corrosion, its extent being strongly a function of cell potential. Performance losses due to platinum catalyst dissolution and/or sintering have been estimated to be in the order of 2mV/1000 h.