(378r) A LaNi0.9Co0.1O3 Coated Ce0.8Sm0.2O1.9 Composite Anode for Solid Oxide Fuel Cells Fed with Methanol

Solid oxide fuel cells (SOFCs) are promising devices those convert chemical energy in fuels directly into electricity with a high efficiency. The most common anode of SOFCs consists of metallic Ni as the catalyst and electronic conductor and a ceramic phase as the oxygen ionic conductor. The content of Ni is usually higher than 45 vol% to achieve a sufficient electronic conductivity. However, such a high amount of Ni suffers from not only aggregation at a high temperature, which results in the reduction of active sizes and the catalytic activity, but also serious carbon deposition with hydrocarbons as fuels. Here LaNi_0.9Co_0.1O₃ (LNC)-Ce_0.8Sm_0.2O_1.9 (SDC) anodes are prepared and investigated as anode materials of SOFC fed with methanol.

The composite anode is synthesized by impregnation. Nanoparticles of Ni-Co alloy are derived from LNC after reduction. The composite anode shows a sufficient electrical conductivity when the weight ratio of Ni to SDC reaches 0.1, which is much lower than the amount of Ni required in conventional Ni-SDC anodes. The aggregation of Ni-Co nanoparticles in the reduced anode is suppressed by the oxide supporter, resulting in an improved catalytic activity. The single cell with LNC-SDC composite anode and SDC-carbonate composite electrolyte exhibits a maximum power density of 872 mW cm^-2 at 700 ^oC with gasified methanol as the fuel, much higher than that of the cell with a NiCo-SDC anode under the same condition. The amount of carbon deposited on the anode in methanol atmosphere decreases with the decline of the LNC content. The cell with the 10LNC-SDC anode exhibits a stable performance during a 10 h discharge period.