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

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 approximate to 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. A self-assembled robust interfacial layer (CIL) is reported to realize stable zinc anodes in non-flexible and flexible zinc-based energy storage. The CIL containing abundant carboxyl and phenolic hydroxyl groups homogenizes Zn2+ flux, accelerates Zn2+ desolvation-deposition and prevents H+/H2O from corroding zinc anodes, thereby stabilizing the zinc deposition interface. Meanwhile, the CIL@Zn anodes with firmly anchored CIL can endure diverse deformations.image