Protonation-induced local electronic structure regulation enables confinement-conversion synergy for long-life zinc-iodine batteries.

Aqueous zinc-iodine batteries (AZIBs) have attracted increasing attention due to their high safety, high theoretical capacity and fast iodine redox kinetics. However, the dissolution and shuttle of polyiodides (I3 - and I5 -) in aqueous electrolytes still lead to poor cycling stability and slow iodine conversion kinetics. In this study, we synthesized a protonated porphyrin-based conjugated microporous polymer (p-por-CMP) and utilized it as an iodine-hosting cathode material (I2@p-por-CMP) for AZIBs. The protonation strategy regulates the local electronic structure and induces charge redistribution within the framework, enabling simultaneous polyiodide immobilization and reversible iodine conversion. The I2@p-por-CMP cathode delivers a reversible specific capacity of 229 mAh g-1 at 0.3 A g-1. Even at a high current density of 5 A g-1, it still exhibits an initial specific capacity of 152.9 mAh g-1, with a capacity decay rate of 0.0036% per cycle over 10 000 cycles. Additionally, the assembled pouch cell exhibits good cycling stability along with a capacity of 117 mAh g-1 at 0.2 A g-1 after 50 cycles. This work provides a new research approach for the design of high-performance AZIBs iodine-hosting materials.