In Situ Assembly of Metal-Organic Coordination Polymer Layers Enables Highly Reversible Zn Anodes with a Long Cycle Life of over 6900 h

Zn anodes in aqueous zinc-ion batteries chronically suffer from pernicious side reactions and ineluctable dendrite growth, resulting in inadequate reversibility and suboptimal Coulombic efficiency (CE) and impeding commercialization. Herein, a multifunctional metal-organic coordination polymer layer (FAZ) is constructed on the zinc anode surface (FAZ@Zn) utilizing a simple self-assembly strategy. The zincophilic FAZ interfacial layer with a high Zn2+ transfer number and low nucleation barrier effectively facilitates the de-solvation process, supports the rapid transport of zinc ions, and contributes to the preferential growth of Zn (002) crystal planes, enabling dendrite-free Zn deposition. Furthermore, the FAZ layer, as an interfacial pH regulating layer, effectively inhibits the direct contact between Zn and active water molecules, lowering the severity of side reactions. Consequently, the FAZ@Zn anode furnishes an eminent cycle stability over 6900 h, with a low polarization voltage at 1 mA cm-2 and 1 mA h cm-2 and a boosted CE of 99.88% over 4100 cycles. More encouragingly, when coupled with Na2V6O16<middle dot>3H2O, the FAZ@Zn anode enables the full cell to deliver satisfactory rate performance and a 97% capacity retention over 1600 cycles. This work provides a simple strategy for the effective preparation of highly reversible zinc anodes for high-performance aqueous zinc-ion batteries. Zn anodes in aqueous zinc-ion batteries suffer from side reactions and dendrite growth, hindering reversibility and Coulombic efficiency. A metal-organic coordination polymer layer (FAZ) on the anode surface has been reported to facilitate zinc ion transport and prevent dendrite formation. This FAZ@Zn anode achieves excellent cycle stability and high Coulombic efficiency, improving the electrochemical performance of full cells with Na2V6O16<middle dot>3H2O. image