Nanoconfined homonuclear Mn pairs for efficient oxygen reduction and long-life Zn-air batteries

The nanoconfined environment offers a synergistic combination of physical confinement and electronic regulation, yet its underlying microscopic mechanisms remain to be systematically elucidated. Herein, we fabricate atomically dispersed homonuclear Mn catalytic pairs through the perhalate cascaded oxidation strategy within nanoconfined pores on activated mesoporous carbon spheres (Mn 2 -N-AMC). Finite element method (FEM) simulations and density functional theory (DFT) calculations reveal that nanoconfinement enhances O 2 transport and weakens the adsorption of oxygen intermediates. Furthermore, the bridge adsorption configuration of intermediates on Mn pairs promotes the subsequent O* protonation and reduces the energy barrier for OH* desorption. Consequently, Mn 2 -N-AMC exhibits superior radical scavenging capability and delivers excellent oxygen reduction reaction (ORR) performance with a half-wave potential (E 1/2 ) of 0.90 V and remarkable stability. Additionally, Mn 2 -N-AMC-based aqueous Zn-air batteries (A-ZABs) achieve an ultrahigh power density of 256.7 mW cm −2 and long-life stability (> 800 h). Quasi-solid-state ZABs also display a long-life operation over 100 h across various current densities, with negligible voltage gap decay. This work provides mechanistic insights, advancing the rational design of nanoconfined ORR catalysts for sustainable energy conversion and storage.