Interface‐Engineered Intermediate Temperature Solid Oxide Electrolysis Cell

Abstract

Ceria oxide is one of the most promising ionic conducting oxide electrolytes for intermediate temperature solid oxide electrolysis cells (IT‐SOECs). However, its strong tendency of reducing Ce4+ to Ce3+ leads to severe performance degradation. Herein, an attractive interface engineering approach to construct a micrometer‐thin Ba‐rich oxide layer that inhibits electron shuttling within ceria reduction is reported. Ba cations are first intentionally doped into the fuel electrode as NiO‐BaZr0.1Ce0.7Y0.2O3−δ (NiO‐BZCY) and then diffuse to the interface between NiO‐BZCY and Sm0.2Ce0.8O2−δ (SDC) via a one‐step co‐sintering process. The corresponding electrolyzer delivers a current density of 0.86 A cm−2 at 1.3 V, placing it as one of the best‐performing IT‐SOECs. The cell can reversibly and stably switch between electrolysis and fuel cell modes.