Al-doped La0.5Sr0.5MnO3 as oxide anode for solid oxide fuel cells using dry C3H8 fuel

Abstract

Direct hydrocarbon type solid oxide fuel cells are attractive from simple gas feed process and also high energy conversion efficiency. In this study, La0.5Sr0.5MnO3 (LSM55) perovskite oxide was studied as oxide anode for direct hydrocarbon type solid oxide fuel cell (SOFC). Although reasonable power density like 1 W/cm2 and open circuit voltage (OCV) (1.1 V) at 1273 K was exhibited when H2 was used as fuel, the power density as well as OCV of the cell using LSM55 for anode was significantly decreased when dry C3H8 was used for fuel. After power generation measurement, LSM55 phase was decomposed to MnO and La2MnO4. Effects of various dopants to Mn site in LSM55 were studied and it was found that partial substitution of Mn in LSM55 with other cation, especially transition metal, is effective for increasing maximum power density. In particular, reasonable high power density can be achieved on the cell using Ni-doped LSM55 for anode. On the other hand, Al substitution is effective for increasing stability against reduction and so, dopant effects of Al were studied in more details for dry C3H8 fuel. The power density as well as OCV increased with increasing Al content and the highest power density was achieved at x = 0.4 in La0.5Sr0.5Mn1 − xAlxO3. Among the examined composition, it was found that the cell using La0.5Sr0.5Mn0.6Al0.4O3 anode shows the largest power density (0.2 W/cm2) at 1173 K and high OCV (1.01 V) against dry C3H8 fuel.