Janus Calix[6]Arene Dual-Site Additive Enables Dendrite-Free Aqueous Zn Batteries

Aqueous zinc (Zn) metal batteries hold great promise as safe, low-cost, and sustainable energy storage systems, but their performance is undermined by dendrite growth, hydrogen evolution, and interfacial corrosion. Here, we introduce p-sulfonatocalix[6]arene (SC6A), a water-soluble supramolecular macrocycle, as a Janus-like electrolyte additive which modulates the Zn²⁺ solvation sheath and regulates interfacial ion flux. SC6A features dual functional sites: anionic sulfonates that selectively anchor to the Zn surface and phenolic hydroxyls that coordinate with Zn²⁺ to facilitate desolvation. This dual-site cooperation enables suppression of side reactions, reduces hydrogen evolution reaction (HER), and guides uniform Zn nucleation along the (002) facet. As a result, Zn||Cu cells achieve highly reversible Zn plating/stripping with a Coulombic efficiency of 99.7% over 1300 cycles, while Zn||NH₄V₄O₁₀ full cells maintain 89% capacity after 1500 cycles at practical loadings (7-8 mg cm^-2). Demonstrates practical feasibility in pouch cells, with minimal gas ecolution. These findings establish a molecular-level supramolecular design strategy for interfacial engineering, enabling long-life aqueous Zn metal batteries.