A Simple Sc Doping Strategy to Enhance Electrocatalytic Activity and Stability in Symmetrical Solid Oxide Cells

Abstract

The main barrier to symmetrical solid oxide cells (SSOCs), where the same catalytic materials are used simultaneously as the anodes and the cathodes, is to find a redox-stable catalyst that exhibits superior catalytic activities for both fuel oxidation/reduction and oxygen reduction/evolution reactions. Here, we report a simple strategy by Sc doping La 0.6 Ca 0.4 Fe 0.8 Ni 0.2 O 3− δ (LCFN) with enhanced electrocatalytic activity and stability in SSOCs. La 0.6 Ca 0.4 Fe 0.7 Sc 0.1 Ni 0.2 O 3− δ (LCFSN) oxide has better crystal structural stability, lower coefficient of thermal expansion (TEC) and good conductivity. In addition, LCFSN has lower polarization resistance both in air, CO 2 or H 2 compared with LCFN. Moreover, the SSOCs with LCFSN showed the maximum power densities of 0.332 and 0.234 W cm −2 when operating in humidified hydrogen at 850 °C and 800 °C, respectively, and the cell shows maximum current densities of 1.093 A cm −2 for CO 2 electrolysis at 850 °C and 1.8 V. In addition, the cell also has good stability toward both fuel cell and electrolysis cell. Therefore, this work suggests that B site Sc doping is a promising approach to the redox-stable catalyst for SSOCs.