We have achieved the synthesis of dual-metal single atoms and atomic clusters that co-anchor on a highly graphitic carbon support. The catalyst comprises Ni 4 (and Fe 4 ) nanoclusters located adjacent to the corresponding NiN 4 (and FeN 4 ) single-atom sites, which is verified by systematic X-ray absorption characterization and density functional theory calculations. A distinct cooperation between Fe 4 (Ni 4 ) nanoclusters and the corresponding FeN 4 (NiN 4 ) atomic sites optimizes the adsorption energy of reaction intermediates and reduces the energy barrier of the potential-determining steps. This catalyst exhibits enhanced oxygen reduction and evolution activity and long-cycle stability compared to counterparts without nanoclusters and commercial Pt/C. The fabricated Zn−air batteries deliver a high power density and long-term cyclability, demonstrating their prospects in energy storage device applications.

Single-atom catalysts (SACs) with high atom utilization and outstanding catalytic selectivity are useful for improving battery performance. Herein, atomically dispersed Ni−N 4 and Fe−N 4 dual sites coanchored on porous hollow carbon nanocages (Ni−Fe−NC) are fabricated and deployed as the sulfur host for Li−S battery. The hollow and conductive carbon matrix promotes electron transfer and also accommodates volume fluctuation during cycling. Notably, the high d band center of Fe in Fe−N 4 site demonstrates strong polysulfide affinity, leading to an accelerated sulfur reduction reaction. Meanwhile, Li 2 S on the Ni−N 4 site delivers a metallic property with high S 2p electron density of states around the Femi energy level, enabling a low sulfur evolution reaction barrier. The dual catalytic effect on Ni−Fe−NC endows sulfur cathode high energy density, prolonged lifespan, and low polarization.