Graphitic Nitrogen-Regulated Direct I2/I- Conversion to Achieve Fast Kinetics and Stability for Zn-I2 Batteries.

Iodine (I2) cathodes for aqueous Zn-I2 batteries suffer from sluggish redox kinetics and severe polyiodide shuttling, resulting in poor utilization and cycling stability. Herein, graphitic nitrogen-enriched carbonized polymer dots (CPDs) with a core-shell structure are integrated with a self-supporting porous carbon framework to construct a graphitic nitrogen-regulated porous carbon host. The porous framework provides abundant space for iodine accommodation and accessible pathways for mass transport, while CPDs introduce graphitic-N sites that strengthen iodine-host interactions and facilitate interfacial electron transfer. Their cooperative action favors a dominant direct I2/I- conversion pathway with substantially suppressed accumulation of soluble polyiodide species, thereby enabling fast iodine redox kinetics and excellent cycling stability. Benefiting from these synergistic effects, the optimized PCF-CPDs/I2-0.2 cathode delivers a high specific capacity of 146.1 mAh g-1 at 0.3 A g-1 with 99.6% capacity retention over 500 cycles. At 1 A g-1, it maintains 117.5 mAh g-1 with 87.1% retention after 4000 cycles. This work demonstrates that coupling porous confinement with CPDs-mediated interfacial regulation provides an effective strategy for developing high-performance Zn-I2 batteries.