Heteroengineered Fe<sub>2</sub>N/CrN<sub>x</sub> with Accelerated Proton-Coupled Electron Transfer for Efficient Oxygen Reduction in Aluminum-Air Batteries.

Zhang, Shuya; Chen, Qiming; Zheng, Liangyu; Cen, Mingjun; Luo, Xinyu; Zhao, Pengwei; Zhang, Qicheng; Li, Yang et al. · Adv Mater · 2026

basic_science · Level V

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Abstract

The sluggish kinetics of the oxygen reduction reaction (ORR) impede the widespread adoption of renewable energy technologies. Here, a heterostructured Fe<sub>2</sub>N/CrN<sub>x</sub>@NC catalyst is presented, where CrN<sub>x</sub> clusters promote H<sub>2</sub>O dissociation and, in concert with Fe<sub>2</sub>N nanoparticles, optimize oxygen intermediates adsorption within an N-doped carbon matrix. The CrN<sub>x</sub>-induced synergy is further confirmed by in situ Raman and infrared spectroscopy, kinetic isotope effect measurements, and theoretical analyses, which collectively reveal that the elaborate Fe<sub>2</sub>N-CrN<sub>x</sub> interface is pivotal in accelerating proton-coupled electron transfer for ORR. As a result, Fe<sub>2</sub>N/CrN<sub>x</sub>@NC achieves a half-wave potential of 0.935 V in 0.1 m KOH, exceeding Pt/C. When deployed as the air cathode in aluminum-air batteries, Fe<sub>2</sub>N/CrN<sub>x</sub>@NC enables a high discharge voltage at 100 mA cm<sup>-2</sup> and an outstanding specific capacity of 2286 mA h g<sub>Al</sub> <sup>-1</sup>. This heterostructure engineering strategy, cooperatively manipulating water dissociation and intermediate adsorption, provides a generalized design paradigm for efficient aluminum-air battery cathodes.