(180c) Improved Activity and Stability of Ni-Based Anode for Direct Methanol–Fueled Solid Oxide Fuel Cells

Mo is utilized to modify the Ni- Ce_0.8Sm_0.2O_1.9 (SDC) anode. The NiO-MoO₃-SDC anode materials are prepared by impregnation technique, which are reduced to SDC and Ni-Mo alloy phases in H₂ atmosphere. Solid oxide fuel cells (SOFCs) with Ni-Mo-SDC composite anodes are fabricated and tested with methanol as fuel. The addition of Mo improves the catalytic activity for methanol pyrolysis and the resistance to carbon deposition of Ni-SDC anode. The electrochemical performance test demonstrates that the addition of Mo into Niâ??SDC anode effectively improves performance and stability of the single cell with methanol as fuel at 700 ^oC. The anode with a mole ratio of Mo to Ni of 0.03:1 (Ni-3Mo-SDC) exhibits the lowest polarization resistance. The cell with that anode and SDC-carbonate composite electrolyte exhibits a maximum power density of 680 mW cm^-2 at 700 ^oC, as shown in Fig. 1. The stability of the cell is enhanced with the increase of the content of Mo in the anode.

In order to further improve the cell performance and stability, rare earth elements (La, Pr and Sm) are introduced into Ni-3Mo-SDC. The effects of La, Pr and Sm addition on the catalytic activity for methanol pyrolysis and coking resistance of the Ni-3Mo-SDC anode are examined. The electrochemical performance of the SOFC is enhanced with introducing La and Sm into the anode. The cell with La addition in the anode shows a maximum power density of 765 mW cm^-2 at 700 ^oC with methanol as fuel. The addition of La, Pr and Sm into Ni-3Mo-SDC anode improves the stability of the cell, which is mainly attributed to the decreased amount of carbon deposition with a high graphitization degree.