Toward High CO Selectivity and Oxidation Resistance Solid Oxide Electrolysis Cell with High-Entropy Alloy
Jun Tong, Na Ni, Baowen Zhou, Chongqing Yang, Kolan Madhav Reddy, Hengyong Tu, Yu-Si Liu, Zhe Tan, Longkai Xiang, Haozhen Li, Xing Zhou, Yunyi Zhang, Yixin Li, Hanchao Zhang, Lei Zhu, Zhen Huang
Abstract
Ni-based cermet materials still persist as pronounced challenges for electrocatalysts in solid oxide electrolysis cells (SOECs), due to their insufficient CO 2 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 H 2 O and CO 2 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 CO 2 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 CO 2 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.