Ceramic Lithium Ion Conductor to Solve the Anode Coking Problem of Practical Solid Oxide Fuel Cells

Abstract

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. For practical solid oxide fuel cells (SOFCs) operated on hydrocarbon fuels, the facile coke formation over Ni-based anodes has become a key factor that limits their widespread application. Modification of the anodes with basic elements may effectively improve their coking resistance in the short term; however, the easy loss of basic elements by thermal evaporation at high temperatures is a new emerging problem. Herein, we propose a new design to develop coking-resistant and stable SOFCs using Li<sup>+</sup>-conducting Li<inf>0.33</inf>La<inf>0.56</inf>TiO<inf>3</inf> (LLTO) as an anode component. In the Ni/LLTO composite, any loss of surface lithium can be efficiently compensated by lithium diffused from the LLTO bulk under operation. Therefore, the SOFC with the Ni/LLTO anode catalyst layer yields excellent power outputs and operational stability. Our results suggest that the simple adoption of a Li<sup>+</sup> conductor as a modifier for Ni-based anodes is a practical and easy way to solve the coking problem of SOFCs that operate on hydrocarbons.