Dual-Affinity Host Engineering for Highly Reversible Zinc-Iodine Batteries

Aqueous zinc-iodine (Zn-I₂) batteries are promising for large-scale energy storage, yet their practical development is impeded by the coupled degradation of both electrodes, including instability Zn anode and sluggish iodine kinetics of cathode. Existing approaches typically focus on individual optimization of each electrode, limiting full cell to achieve synergistic enhancement and inevitably increases system complexity. Herein, a dual-affinity three-dimensional host is constructed by integrating one-dimensional carbon nanotubes with two-dimensional vermiculite nanosheets. The incorporation of vermiculite overcomes the intrinsically low polarity and weak adsorption capability with active material of the conventional 3D carbon frameworks. Benefiting from the densely stacked hybrid architecture with high mechanical strength, excellent electrical conductivity and dual affinity toward Zn and polyiodides, the 3D host concurrent regulate Zn deposition and iodine conversion chemistry. The zincophilic vermiculite regulate Zn²⁺ flux, lower the nucleation barrier and promote uniform deposition, while the porous structure effectively suppress polyiodide shuttling through synergistic physical confinement and chemical anchoring. Consequently, the Zn composite anode exhibits remarkable cycling stability over 3000 cycles at 20 mA cm^-2 at 60% depth-of-discharge, whereas the integrated Zn-I₂ full cell maintains 90.0% capacity retention after 2000 cycles. This work offers a route for designing durable, highly efficient Zn-I₂ batteries.