Core–shell structured Li0.33La0.56TiO3 perovskite as a highly efficient and sulfur-tolerant anode for solid-oxide fuel cells

Abstract

Solid oxide fuel cells (SOFCs), which directly convert chemical energy into electricity, have several advantages, such as fuel flexibility and low emissions. Unfortunately, the performance and stability of SOFCs with state-of-the-art Ni-based anodes are sensitive to impurities, such as sulfur, which is a common component of practical fuels, including natural gas and renewable biogas. The development of sulfur-tolerant anode materials is important for successfully operating SOFCs with sulfur-containing practical fuels. In this study, a core–shell architecture was fabricated from solution infiltration and was evaluated as a sulfur-tolerant anode for SOFCs. For the first time, we used a lithium conductive material, Li0.33La0.56TiO3 (LLTO, perovskite oxide), as the shell for anodic reactions. The resulting cell delivered higher electrochemical activities than similar cells, with widely used sulfur-tolerant perovskite anodes. In addition, the cell with the core–shell structured anode demonstrated favorable stability over 70 hours' operation when using 1000 ppm H2S–H2 fuel at 800 °C. In contrast, the cell with an anode composed of nanoparticles failed after only 5.5 hours under the same operation conditions. This study offers a new strategy for developing highly sulfur tolerant and efficient anodes for SOFCs.