High-performance (La,Sr)(Cr,Mn)O3/(Gd,Ce)O2−δ composite anode for direct oxidation of methane

Abstract

A novel (La,Sr)(Cr,Mn)O3/(Gd,Ce)O2−δ (LSCM/GDC) composite electrode is developed and applied as solid oxide fuel cell (SOFC) anode for direct oxidation of methane. The optimum composition of the composite anode is 33 wt.% LSCM and 67 wt.% GDC. At an output current density of 0.5 A cm−2, the overpotential of the anode in wet H2 and CH4 at 850 °C is 0.073 and 0.248 V (i.e., an anodic resistance of 0.146 and 0.496 Ω cm2), respectively. The oxidation of CH4 on the composite anode is primarily studied by means of electrochemical impedance spectroscopy under different temperatures and a dc bias. The stability of the LSCM/GDC composite anode is evaluated under different current loadings in wet CH4 at 850 °C for 50 h. The results show that the developed LSCM/GDC composite anode has high stability in CH4 fuel and possesses good electrochemical performance that is comparable with a Ni cermet anode.