Long-Term Sulfur Tolerance of Solid Oxide Fuel Cells with Alternative Titanate-Based Fuel Electrodes

Abstract

Currently, solid oxide fuel cell systems rely on upstream desulfurization units to prevent sulfur poisoning of the state-of-the-art anodes based on Ni-cermets. Next-generation anode materials should be sulfur tolerant, without compromising the performance, to reduce system complexity and cost. In this study, all-ceramic La0.4Sr0.4Fe0.03Ni0.03Ti0.94O3 (LSFNT) anodes, infiltrated with Ni:Ce0.8Gd0.2O1.9 (CGO) or FeNi:CGO electrocatalysts, were integrated into large-area electrolyte supported cells. The cells were tested together with a SoA cell with Ni/CGO cermet anode in a short stack configuration using reformed grid natural gas and an upstream, bypassable desulfurization unit. The cell performances before exposure to sulfur were similar for all cell types at 850 °C. Exposure to sulfur revealed different degradation mechanisms. TheSoA cell shows a fast, initial degradation followed by limited further degradation. In contrast, the FeNi:CGO infiltrated LSFNT anode appears sulfur tolerant initially, followed by accelerated degradation of >50% kh-1 over long-term sulfur exposures. The Ni:CGO infiltrated LSFNT anode is remarkably sulfur tolerant.