Interfacial Electronic Nanoarchitectonics for Sustainable Zn─I ₂ Batteries

Aqueous zinc-iodine batteries (AZIBs) are intrinsically safe and cost-effective, yet their performance is limited by sluggish iodine redox kinetics, poor conductivity, and severe polyiodide shuttling. Herein, we design a heterostructure cathode by depositing titanium nitride (TiN) onto biomass-derived porous nitrogen-doped carbon (PNC), forming a tailored PNC@TiN interface that markedly enhances electronic conductivity and regulates iodine electrochemistry. Density functional theory (DFT) calculations reveal pronounced interfacial charge redistribution with an upward shift of the Ti d-band centeri, enabling strong Ti─I bonding through orbital coupling among Ti 3d, C/N 2p, and I 5p states, as well as improved iodine affinity with suppressed polyiodide shuttle. Accordingly, the AZIB with the PNC@TiN cathode exhibits a high reversible capacity of 166.9 mAh g^-1 after 21,000 cycles at 2.0 A g^-1 (95.4% retention), and exceptional durability over 66,000 cycles at 5.0 A g^-1 with an ultralow capacity decay of 0.00028% per cycle. Furthermore, the as-assembled pouch cells achieve 176.1 mAh g^-1 with negligible degradation, highlighting their practical viability. This work underscores the crucial role of interfacial electronic nanoarchitectonics in modulating iodine chemistry, and presents a sustainable strategy to repurpose biomass into advanced energy-storage materials.