STUDIES ON MOLTEN CARBONATE FUEL-CELL WITH AND WITHOUT DEPOLARIZER

A fuel cell using solid fuel (coal) in a mixture of molten alkali carbonate electrolyte with molten lead cathode and powdered coal (pressed in to a disc) anode, operating at a temperature of 600-degrees-C has been investigated in the presence as well as absence of a depolariser. An open circuit voltage of about 500 mV is recorded without depolariser which falls to 260 mV on drawing a current of 80 mA/cm2. Different types of polarisation are observed. Addition of depolariser increases the open circuit voltage up to 580 mV, and a constant current upto 90 mA/cm2 and more can be drawn at a voltage of 560 mV. The efficiency of the cell with and without depolariser is 30% and 18% respectively. Use of paste electrodes, incorporating MgO/SiO2 in the molten electrolyte as a paste, minimises electrode flooding and leads to significant improvement in the cell performance.