Single-chamber solid oxide fuel cells at intermediate temperatures with various hydrocarbon-air mixtures

Thr performance of a single-chamber solid oxide fuel cell (SOFC) was studied between 350 and 900 degrees C in flowing mixtures of methane, ethane, propane, or liquefied petroleum gas and air with a fuel/air volume ratio of one, where their oxidation proceeded safely without explosion. Among all tested electrode materials, Ni-Ce(0.8)Sm(0.2)O(1.9) cermet and Sm(0.5)Sr(0.5)CoO(3) oxide functioned best as the anode and cathode, respectively, in various gas mixtures. A cell constructed from a La(0.9)Sr(0.1)Ga(0.8)Mg(0.2)O(3) electrolyte with the two electrodes generated >900 mV in a methane-air mixture between 600 and 800 degrees C and in an ethane-air mixture between 450 and 650 degrees C. A small electrode reaction resistance resulted in increasing power density with decreasing electrolyte thickness. The peal, power density at 450 degrees C increased from 34 to 101 mW cm(-2) with decreasing electrolyte thickness from 0.50 to 0.18 mm. The working mechanism of the single-chamber SOFC at different temperatures was also studied by measuring the catalytic activities of the two electrodes for partial oxidation of the hydrocarbons. (C) 2000 The Electrochemical Society. S0013-4651(00)03-011-1. All rights reserved.