A hierarchical porous tin host for dendrite-free, highly reversible zinc anodes

Metallic zinc (Zn), featuring high specific capacity, low redox potential, and low cost, is a promising anode material for next-generation rechargeable aqueous batteries. However, Zn anodes suffer from the dendrite formation and side reactions during the plating/stripping process, which severely hinder their practical applications. To simultaneously address these issues, we create a hierarchical porous framework by electroless plating a conformal nanoporous tin (Sn) layer on a copper (Cu) mesh as a host (NSH) for the Zn anode. Both experimental and numerical results reveal that the newly developed NSH offers abundant Zn nucleation sites, homogenizes both the ion flux and electric field at the electrode surface, and suppresses side reactions with the high hydrogen evolution reaction overpotential of Sn, thus leading to dendrite-free Zn deposition and a highly reversible plating/stripping process. As a result, the asymmetric Zn||NSH cell achieves a coulombic efficiency (CE) of 99.0% for over 200 cycles at 2 mA cm−2. The cell with the pristine Cu mesh host (PCH), in comparison, exhibits a CE of 97.7% and suffers from short-circuits after 50 cycles. Moreover, the Zn@NSH anode enables the Zn-MnO2 full cell to deliver a high capacity of 164 mAh g−1 and maintain a retention rate of 86.2% after 1200 cycles at 1 A g−1. By contrast, the capacity of the cell with the Zn@PCH anode decays to 55.2 mAh g−1 after 800 cycles, corresponding to a retention rate of 38.1%. This work opens a new avenue to develop advanced three-dimensional Zn metal anodes for high-performance rechargeable aqueous batteries.