Heteroatom-Modulated Asymmetric Cobalt Single-Atom Catalysts on MOF-Derived Carbon Enabling Durable Zinc-Iodine...

The rational design of catalytic host materials with optimized electronic structures and confined architectures is crucial for addressing the shuttle effect and sluggish kinetics in aqueous zinc-iodine batteries. In this study, an asymmetric cobalt single-atom catalyst is developed by anchoring Co-N₃P₁ sites on a nitrogen-phosphorus co-doped carbon matrix (Co-N-PC) derived from metal-organic frameworks (MOFs). The coordination engineering of Co centers via phosphorus incorporation disrupts the symmetry of conventional Co-N₄ configurations, enhancing charge redistribution and reducing the energy barrier for iodine dissociation as confirmed by density functional theory calculations. Systematic optimization reveals that moderate Co and P doping balances active sites and electronic conductivity, achieving strong chemical adsorption of polyiodides while maintaining structural stability. In situ Raman and UV-Vis spectroscopies confirm effective confinement of iodine species and reversible iodine conversion. The optimized C3/I₂ cathode exhibits exceptional cyclability, retaining a specific capacity of 100.6 mA h g^-1 after 50,000 cycles at 5 A g^-1. Furthermore, practical applicability is demonstrated in flexible soft-pack batteries and 3D-printed/screen-printed micro-batteries, showing its potential for scalable energy storage. This work presents a heteroatom-modulation strategy for designing efficient catalytic hosts in conversion-type batteries.