Toward High CO Selectivity and Oxidation Resistance Solid Oxide Electrolysis Cell with High-Entropy Alloy

Abstract

Ni-based cermet materials still persist as pronounced challenges for electrocatalysts in solid oxide electrolysis cells (SOECs), due to their insufficient CO2 catalytic efficiency and inferior resistance to oxidation. In this paper, a (Fe,Co,Ni,Cu,Mo) quinary high-entropy alloy is explored as an alternative cathode material, offering enhanced performance in the co-electrolysis of H2O and CO2 for renewable syngas production. In comparison to traditional nickel-based cathodes, an assembled SOEC employing the as-designed quinary high-entropy alloy exhibits a remarkable increase in CO2 conversion capacity and significantly enhanced oxidation resistance. In addition, the electrolysis current density increases by 18%, and a stability test for more than 110 h reveals no degradation. Moreover, the stability can be maintained for up to 40 h even without any protective gas. Morphological and spectroscopic analyses, coupled with density functional theory (DFT) calculations, elucidate that the high-entropy effect facilitates surface electron redistribution, which in turn contributes to the measurable activity by reducing the energy barrier of CO2 activation. Notably, the superior resistance to oxidation primarily originates from the in situ-formed spinel phase under oxidation conditions. This study demonstrates the satisfying performance of high-entropy alloys as cathode materials in SOEC, validating their high application potential in this field.

Advancements and prospects of perovskite-based fuel electrodes in solid oxide cells for CO2 electrolysis to CO

“…4d ). 55 Due to larger particle sizes, predominantly having a magnitude of several tens of micrometers, the high-entropy fuel electrode exhibited a reduced specific surface area compared to the perovskite electrode. Moreover, after the stability test, slight oxidation of the alloy occurred.…”

A Highly Active and Robust Air Electrode for Reversible Protonic Ceramic Cells: Advanced Performance Achieved by Low-Lewis-Acid-Strength Cation Doping Strategy

“…Regulating the energy composition by developing a clean power system is a beneficial way to alleviate the pressure on the environment. − Among all the renewable energy sources, reversible protonic ceramic cell (RPCC) technology advances discontinuous energy systems (solar, wind, and tides) by higher functionality and reliability from a long-term perspective. In the dual-mode operation, electricity or H 2 can be generated selectively in the reversible processes. , Evolved from the traditional oxygen ion conductive cells, the proton conductive RPCCs show the significant superiority of structural robustness and low maintenance costs owing to the lowered operation temperature. , With the progressions of the RPCC technology, the ever-lowering working temperature enables the flexible selection of constituent materials, while also bringing new challenges for the air electrode. , …”