Novel application of aluminum salt for cost-effective fabrication of a highly creep-resistant nickel–aluminum anode for a molten carbonate fuel cell

A one-step sintering process using aluminum acetate as an aluminum source is used to fabricate a nickel-based anode for a molten carbonate fuel cell (MCFC). The process is designed to replace existing partial or full oxidation and reduction processes, which are quite complicated and expensive. The aim is to simplify the fabrication process of a highly creep-resistant Ni–Al anode and eventually to contribute to the commercialization of a MCFC. Considering the solubility limit of Al in Ni, two types of anodes, Ni–2.5 wt.%Al and Ni–5 wt.%Al, are fabricated by sintering at either 1000 or 1100 °C for 2 h in a 99.5% H2 atmosphere. After characterizing the resulting material by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy, it is confirmed that among the anodes fabricated, the Ni–5 wt.%Al sample sintered at 1100 °C contained the most suitable Al2O3 in a dispersed form. A 100-h creep test reveals that the creep strain of the anode has the lowest value of 1.3% compared with the other anodes. This value is superior to the creep strain of 2.3% obtained from a Ni–5 wt.%Al anode using Al powder as a fine Al2O3 dispersion source in a Ni-base anode matrix. A single cell using the Ni–5 wt.%Al anode fabricated in this study shows a stable closed-circuit voltage of 0.795 V for 1000 h at 150 mA cm−2.