Constructing Bipolar Dual-Active Sites through High-Entropy-Induced Electric Dipole Transition for Decoupling Oxygen Redox.
basic_science · Level V
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- Record sourced from PubMed, PMID 38602072.
- Also identified by DOI 10.1002/adma.202401018.
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Abstract
It remains a significant challenge to construct active sites to break the trade-off between oxidation and reduction processes occurring in battery cathodes with conversion mechanism, especially for the oxygen reduction and evolution reactions (ORR/OER) involved in the zinc-air batteries (ZABs). Here, using a high-entropy-driven electric dipole transition strategy to activate and stabilize the tetrahedral sites is proposed, while enhancing the activity of octahedral sites through orbital hybridization in a FeCoNiMnCrO spinel oxide, thus constructing bipolar dual-active sites with high-low valence states, which can effectively decouple ORR/OER. The FeCoNiMnCrO high-entropy spinel oxide with severe lattice distortion, exhibits a strong 1s→4s electric dipole transition and intense t<sub>2g</sub>(Co)/e<sub>g</sub>(Ni)-2p(O<sub>L</sub>) orbital hybridization that regulates the electronic descriptors, e<sub>g</sub> and t<sub>2g</sub>, which leads to the formation of low-valence Co tetrahedral sites (Co<sub>th</sub>) and high-valence Ni octahedral sites (Ni<sub>oh</sub>), resulting in a higher half-wave potential of 0.87 V on Co<sub>th</sub> sites and a lower overpotential of 0.26 V at 10 mA cm<sup>-2</sup> on Ni<sub>oh</sub> sites as well as a superior performance of ZABs compared to low/mild entropy spinel oxides. Therefore, entropy engineering presents a distinctive approach for designing catalytic sites by inducing novel electromagnetic properties in materials across various electrocatalytic reactions, particularly for decoupling systems.