La0.6Sr0.4Co0.2Fe0.8O3-δ nanoparticles modified Ni-based anode for direct methane-fueled SOFCs

Abstract

Direct utilization of methane in solid oxide fuel cells (SOFCs) is highly desirable, due to the merits of cost, simplicity and energy saving. However, the most commonly used Ni/YSZ anode suffers from carbon deposit issue under CH4. Here, a novel composite anode is developed to solve the problem, where La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) perovskite-type mixed ionic and electronic conductor (MIEC) is used to modified the anode by infiltration method. Simultaneously, LSCF/YSZ nano-structure cathode is obtained using infiltration method as well, which remarkably simplified the preparation process and is in favor of the practical applications. High electrochemical activity is demonstrated for this cell with a peak power density of 705 mWcm−2 under H2 and 486 mWcm-2 under CH4 at 800 °C. Durability test suggests the stability of cell in CH4 is dramatically improved, and it operates for 100h with little degradation under 0.3 Acm−2 and 750 °C. Results show that LSCF NPs, which are partially decomposed to (Sr,La)2(Co,Fe)O4 with CoFe alloy phase and disperse on the anode as a very thin layer in fuel atmosphere, dramatically enhance the coking resistance of anode. The work delivers an efficient way for direct CH4 fueled SOFC.