Degradation of the Components in Molten Carbonate Fuel Cells with Li/Na Electrolyte

Abstract

The Li/Na carbonate is expected to be the one of the candidates for the advanced electrolyte of Molten Carbonate Fuel Cells (MCFC) especially under the pressurized operation. After the long-term operation of cells with the Li/Na carbonate, the Ni deposition in matrices, degradation of cathodes, matrices and cathode current collectors were analyzed. With the Li/Na carbonate, the amount of the Ni deposition and the particle growth of NiO in cathodes were suppressed by the less solubility of NiO. Moreover, there were no detectable differences on both the particle growth and the phase transformation of γ-LiAlO₂ in the matrices. The extraordinary effects on the corrosion penetrations and the electrolyte losses of the cathode current collectors by the Li/Na electrolyte were not detected. Therefore, the MCFCs with the Li/Na carbonate are expected to have a longer endurance and a lower decay rate compared with conventional cells with the Li/K carbonate, because of less dissolution of the NiO cathode related to both the short circuiting and the lower increase of polarization due to the structural changes of cathodes.