A mesoporous N-doped carbon host enabling entrapment-catalysis of iodine for Ultrastable zinc–iodine batteries

The zinc–iodine (Zn I 2 ) battery is a promising, low-cost energy-storage technology, but its viability is compromised by the high solubility and shuttle effect of iodine species. Herein, we engineer a mesoporous nitrogen-doped carbon (NC) host that simultaneously confines and catalyzes the I 3 − /I 2 /I − redox conversion. The resulting Zn I 2 battery delivers a high specific capacity of 220 mAh g −1 at 2.0 A g −1 , remarkable rate performance up to 40 A g −1 , and exceptional cycling stability with 98.2% capacity retention after 10,000 cycles at 10 A g −1 . Integrated experimental and theoretical studies demonstrate that engineered mesoporosity provides optimal sites for anchoring iodine species, while the pyridinic-N dopants enhance adsorption and facilitate rapid, reversible redox kinetics. This work establishes an effective host design strategy based on entrapment-conversion synergy for high-performance, durable Zn I 2 batteries. • Mesoporous N-doped carbon enables iodine confinement and fast redox. • Entrapment–conversion synergy suppresses polyiodide shuttle effect. • Diffusion-controlled I − /I3 − /I2 redox confirmed by electrochemical analysis. • High capacity (220 mAh g − 1) and rate up to 40 A g − 1 achieved.