Ultrafast Tea Polyphenol Surface Conditioning Creates a Zincophilic Interphase for Durable Zinc Anodes

The practical deployment of aqueous zinc-ion batteries (AZIBs) is critically limited by uneven Zn²⁺ flux, uncontrolled dendrite growth, and concurrent parasitic reactions-notably the hydrogen evolution reaction (HER) and anode corrosion-arising from interfacial and kinetic instability during repeated plating/stripping cycles. These issues originate at the zinc anode-electrolyte interface, underscoring the necessity of advanced interfacial engineering. Here, we report a surface-confined polyphenol-derived interphase formed on zinc foil through a 1 min dip treatment in a dilute aqueous solution of a commercial tea polyphenol (TP) mixture (0.02 M); after rinsing and drying, the modified electrode is cycled in a conventional electrolyte to which no TP is deliberately added. This interphase promotes more homogeneous nucleation behaviour through coordination between phenolic oxygen-containing moieties and Zn²⁺, improves electrolyte contact homogeneity and perturbs the local water structure to mitigate water-mediated parasitic reactions. The TP-derived surface modification creates a substantially altered interfacial charging environment (Cdl = 47.25 vs. 16.83 µF cm^-2 for bare Zn) that facilitates more uniform zinc deposition. Symmetric cells with TP@Zn anodes demonstrated exceptional cycling stability exceeding 4000 h at 1 mA cm^-2 and 1 mAh cm^-2 (bare Zn fails within ~240 h under identical conditions), while TP@Zn//V₂O₅ full cells retained 56.2% capacity after 300 cycles at 0.5 A g^-1 with a higher median discharge voltage than bare Zn cells, substantially outperforming the latter (31.1% retention). Density functional theory calculations using the selected cluster models yield a markedly more negative electronic interaction energy for Zn²⁺ with an EGCG model ligand (-10.97 eV) than with H₂O (-4.49 eV), qualitatively supporting preferential coordination of Zn²⁺ by phenolic oxygen sites. This work presents a green, facile and potentially scalable interfacial regulation strategy and advances the understanding of natural polyphenols as pre-formed surface conditioners for highly reversible metal anodes.