A Unique Quadruple-Site System Integrating Fe-N<sub>4</sub> Sites and Zn Atomic Clusters for Oxygen Reduction Reaction and Wide-Temperature Zn-Air Batteries.

Zhang, Ying; Chen, Li Bo; Liu, Xu; Li, Jian; Wen, Zi; Wang, Guoyong; Zhang, Hong; Yang, Chun Cheng et al. · Nano Lett · 2025

basic_science · Level V

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Abstract

Fe-N-C single-atom catalysts (SACs) featuring Fe-N<sub>4</sub> configurations face challenges in the simultaneous enhancement of intrinsic oxygen reduction reaction (ORR) activity and long-term stability. Herein, we developed a unique quadruple-site cooperative system through a 90 s ultrafast thermal shock strategy, where most Zn atomic clusters are surrounded by two closely neighboring and a further Fe-N<sub>4</sub> sites (Fe<sub>SA</sub>/Zn<sub>AC</sub>-N-C). Density functional theory and molecular dynamics simulations jointly reveal that proximal Fe-N<sub>4</sub>-modified Zn atomic clusters mediate O<sub>2</sub> adsorption/activation/hydrogenation, while distal Fe-N<sub>4</sub> sites facilitate H<sub>2</sub>O formation/desorption. This synergistic dual-active-center configuration achieves a positive half-wave potential of 0.90 V and superb durability. The constructed aqueous Fe<sub>SA</sub>/Zn<sub>AC</sub>-N-C-based Zn-air batteries demonstrate a large maximum power density of 161.5 mW cm<sup>-2</sup>, a high specific discharge capacity of 792.7 mAh g<sup>-1</sup>, and stable operation over 1500 cycles. In addition, the fabricated quasi-solid-state Zn-air batteries also maintain favorable operation across a wide temperature range (-30 to 60 °C) and at the ampere scale.