Self‐Assembled Robust Interfacial Layer for Dendrite‐Free and Flexible Zinc‐Based Energy Storage

Abstract Aqueous zinc‐based energy storage systems (Zn‐ESSs) with intrinsic safety and good electrochemical performance are promising power suppliers for flexible electronics, whereas unstable zinc anodes especially in flexible Zn‐ESSs pose a challenge. Herein, a self‐assembled robust interfacial layer to achieve stable zinc anodes in non‐flexible and flexible Zn‐ESSs is reported. Specifically, zinc anodes and their slowly‐released Zn2+ simultaneously interact with tannic acid molecules in ethanol–water solutions, triggering the self‐assembly of a tannic acid/Zn2+ complex interfacial layer (CIL) that firmly anchors on the zinc anodes. The CIL containing abundant carboxyl and phenolic hydroxyl functional groups provides rich zincophilic sites to homogenize Zn2+ flux and accelerate Zn2+ desolvation‐deposition, and traps H+/H2O species to prevent them from corroding zinc anodes, thereby stabilizing the zinc deposition interface. Consequently, the CIL@Zn anodes present superior stability with an operation lifetime exceeding 700 h even at 5 mA cm−2 (28 times longer than that of bare zinc anodes) and ultrahigh cumulative plated capacity of ≈1.8 Ah cm−2. The firm anchoring of the CIL enables the CIL@Zn anodes to endure diverse deformations, thus realizing highly flexible CIL@Zn anode‐based Zn‐ESSs. This work provides thinking in designing stable and flexible zinc anodes, promoting the development of flexible zinc‐based energy storage.