Boosting Oxygen Reduction via Nanotwinned High‐Entropy Aerogels With Deficient Pd Coordination and Multi‐d‐Orbital Hybridization for Zinc‐Air Battery Applications

ABSTRACT

High‐entropy alloys (HEAs) offer exceptional opportunities for electrocatalytic applications, yet achieving precise control over their atomic‐scale defects and electronic properties remains a substantial challenge. Herein, high‐entropy alloy aerogels (HEAAs) with a hierarchical porous structure are successfully constructed through systematic thermodynamic and electronic structure analysis combined with particle self‐assembly technology. The lattice distortion produces a local micro‐strain field and nano‐twin boundaries, which destroy the typical atomic periodicity and lead to an unsaturated Pd coordination environment, thereby increasing the density of active sites. In addition, we observe electron transfer from 3d (Cu, Ni, Co) to 4d (Pd) and 5d (Pt) elements, demonstrating effective multi‐orbital electron regulation. The optimized HEAAs exhibit excellent bifunctional properties, with a potential difference of 0.64 V and a high kinetic current density of 27.9 mA·cm ⁻² , which are much better than those of commercial catalysts. When applied to the zinc‐air battery, it exhibits long cycle stability of over 600 h. Theoretical calculations show that the strong anti‐bonding effect of PdPtCuNiCo HEAAs weakens the adsorption of OOH*, and its high‐spin electronic configuration promotes the electron transfer to the intermediate O 2p orbital, both of which improve the ORR activity.