Fe-Cu dual-atom sites suppress H2O2 accumulation and fenton corrosion for efficient and durable Zn-Air batteries

Fe-Cu dual-atom sites were prepared through pre-coordination and ultrafast Joule heating. • FeCu-N-MCS displays a large E 1/2 , low H 2 O 2 yield and excellent stability. • FeCu-N-MCS suppresses H 2 O 2 accumulation through hydrogen peroxide reduction reaction (HPRR). • Cooperative interaction of dual-atom sites reduces the energy barrier of OH* desorption for 4e⁻ ORR. • Zn-air batteries achieve ultrahigh power density and remarkable charge/discharge stability. The oxygen reduction reaction (ORR) governs the power output and cycling lifetime of metal-air batteries. Fe-N-C single-atom catalysts are among the most promising precious-metal-free ORR electrocatalysts, but their durability is often compromised by H 2 O 2 generated through the competing two-electron ORR pathway, which can trigger Fenton reactions and radical-induced catalyst degradation. Herein, Fe-Cu dual-atom sites anchored on microporous carbon spheres (FeCu-N-MCS) are constructed through a pre-coordination strategy followed by rapid Joule heating. Combined experimental results and density functional theory (DFT) calculations reveal that the electronic coupling between Fe and Cu sites lowers the energy barrier of the rate-determining step for the four-electron ORR pathway. More importantly, the Fe-Cu dual-site configuration enables spontaneous hydrogen peroxide reduction reaction (HPRR) at Fe sites and significantly facilitates OH* desorption during HPRR, thereby suppressing H 2 O 2 accumulation and alleviating Fenton-type oxidative degradation. Consequently, FeCu-N-MCS delivers outstanding ORR performance with a half-wave potential of 0.91 V, a low H 2 O 2 yield below 2.91%, and 91.05% current retention after 100 h. Aqueous Zn-air batteries (A-ZABs) assembled with FeCu-N-MCS achieve a peak power density of 223.73 mW cm −2 and stable cycling for over 1200 h. FeCu-N-MCS-based Quasi-solid-state ZABs (QSS-ZABs) further exhibit an open-circuit voltage (OCV) of 1.52 V and a power density of 246.85 mW cm −2 . This work establishes a dual-atom-site strategy for coupling high ORR activity with H 2 O 2 -resistant durability, offering mechanistic insight into the design of robust precious-metal-free electrocatalysts for advanced metal-air batteries. Download: Download high-res image (220KB) Download: Download full-size image Fe-Cu dual-atom sites were prepared through pre-coordination and Joule heating. The incorporation of Cu sites into Fe-N-MCS not only reduces the energy barrier of the rate-determining step (RDS) to accelerate the 4e⁻ ORR pathway, but also enables spontaneous hydrogen peroxide reduction reaction (HPRR) to suppress H 2 O 2 accumulation and Fenton corrosion. Consequently, the assembled Zn-air batteries achieve remarkable power density and ultra-long cycling stability.