An iron-base oxygen-evolution electrode for high-temperature electrolyzers.

Du, Kaifa; Gao, Enlai; Zhang, Chunbo; Ma, Yongsong; Wang, Peilin; Yu, Rui; Li, Wenmiao; Zheng, Kaiyuan et al. · Nat Commun · 2023

basic_science · Level V

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Abstract

High-temperature molten-salt electrolyzers play a central role in metals, materials and chemicals production for their merit of favorable kinetics. However, a low-cost, long-lasting, and efficient high-temperature oxygen evolution reaction (HT-OER) electrode remains a big challenge. Here we report an iron-base electrode with an in situ formed lithium ferrite scale that provides enhanced stability and catalytic activity in both high-temperature molten carbonate and chloride salts. The finding is stemmed from a discovery of the ionic potential-stability relationship and a basicity modulation principle of oxide films in molten salt. Using the iron-base electrode, we build a kiloampere-scale molten carbonate electrolyzer to efficiently convert CO<sub>2</sub> to carbon and oxygen. More broadly, the design principles lay the foundations for exploring cheap, Earth-abundant, and long-lasting HT-OER electrodes for electrochemical devices with molten carbonate and chloride electrolytes.