A Study on In Situ Sintering of Ni–5 wt % Al Anode for Molten Carbonate Fuel Cells

In situ sintering of a molten carbonate fuel cell (MCFC) anode offers simpler procedure and hence lower cost than conventional ex situ sintering. To develop the in situ sintering anode for an MCFC, the insufficient sintering problem of Ni-based anode, due to the lower in situ sintering temperature (at 650°C) than the ex situ sintering temperature (at 1100°C), should be solved. In this study, to improve sinterability at 650°C, liquid-phase sintering using the low melting element of Sn as an additive was adopted for in situ sintering of Ni-5 wt % Al anode and thus in situ sintering of Ni―Al―Sn anodes was attempted. Ni95―A15―Sn30 (weight ratio) anode among these anodes showed an adequate porosity of 65% and a mean pore size of 3.4 μm for an MCFC anode and fairly creep resistance with a creep strain of 4.0% after a 100 h creep test. After a single-cell test, this anode also showed good performance with an open-circuit voltage (OCV) of 1.12 V and a closed-circuit voltage (CCV) of 1.0 V at a current density of 150 mA/cm 2 and a maximum power density of 420 mW/cm 2 . During the 200 h cell operation, the performance was maintained stably with the OCV in the range of 1.11-1.12 V and the CCV in the range of 0.98-1.00 V.