Interfacial Lewis Acid Chemistry Enabled by Mesoporous MOFs Toward High-Performance Four-Electron Zinc-Iodine...

Zinc-iodine (4e^--Zn─I₂) batteries hold promise for grid-scale energy storage, but their development is hampered by the instability of I⁺ species and sluggish conversion kinetics. Here, we depart from conventional weak-interaction catalyst strategies and establish a strong interfacial Lewis acid chemistry based on mesoporous Zr-UiO-66, achieving effective stabilization of I⁺ species and efficient iodine conversion. Synchrotron characterizations reveal that mesopore engineering via a micelle pre-coordination strategy generates abundant interfacial unsaturated Zr sites with intrinsic Lewis acidity and a reduced coordination number on the pore walls of mesoporous Zr-UiO-66. These Lewis acid sites strongly adsorb and stabilize ICl₂ ^-, and efficiently promote its conversion. Density functional theory calculations confirm the strong electronic coupling between Zr sites and iodine guests and the reduced energy barrier for I⁺/I₂ conversion. Concurrently, mesoporous channels facilitate mass transport, enabling seamless ion and electron transport. The resultant Zr-Meso-UiO-66@I₂ cathode delivers a reversible capacity of 390 mAh g^-1 at 10 C, approaching the theoretical four-electron limit, along with unprecedented cycling stability with 89.7% capacity retention after 40,000 cycles at 100 C. The study offers a novel interfacial Lewis-acid catalysis strategy for activating 4e^--Zn─I₂ batteries.