Directionally Modulated Zinc Deposition by a Robust Zincophilic Cu-Phthalocyanine Protective Layer in Dendrite-Free Aqueous Zinc Ion Batteries.

The directional modulation of zinc (Zn) deposition with further investigation of the dendrite-formation mechanism is vital in artificial anode protective layer for aqueous Zn-ion batteries (AZIBs). Herein, a robust metalated covalent organic framework (CuPc-COF) used as the artificial anode protective layer is proposed, in which the zincophilic sites of π-conjugated periodic skeletons are precisely designed to modulate the directional migration of Zn, the multiple redox-active sites facilitate the Zn confinement and transfer, and the central metal copper (Cu) serves as the inhibitor to eliminate the hydrogen evolution side reactions. By combining theoretical calculations with experiments, the π-conjugated planar CuPc-COF layer is a desired protective coating of AZIB anodes with directionally transport channels and abundant redox active sites, thus inducing two-dimensional deposition of Zn. Attributed to these superiorities, the fabricated CuPc-COF@Zn anode demonstrates excellent cycling lifespan in both symmetrical cell (exceeding 2500 h at 1 mA cm) and full cell with different cathodes (more than 3000 cycles at 1 A g), outperforming most reported zinc anodes with COF-based layers.