An interfacial dual-regulation strategy for ultra-stable 3D Zn metal anodes

Abstract

The development of Zn metal-batteries, which are viewed as one of the most potential alternatives to lithium ion batteries, is severely hindered by sluggish ion diffusion kinetics and uncontrollable dendritic growth for anodes. Herein, we propose an interfacial dual-regulation strategy for the fabrication of 3D Zn anode through the direct in-situ treatment of benchmark Zn foil. Both rapid ion migration dynamics and homogeneous bottom-up Zn2+ deposition are achieved due to the unique open nanoarray structure with superhydrophilic and zincophilic interface to the electrolyte. Theoretical calculations and finite element simulations reveal this design can effectively redistribute Zn2+ and increase ion flux with a long-lasting 3D diffusion mode, enabling exceptional reversibility during Zn plating/stripping. The as-prepared anode therefore achieves an ultralong lifespan over 3000 h along with high rate capability even at 40 mA cm−2 (depth of discharge ≈ 68.4%). Furthermore, its practical feasibility is validated by a superior capacity retention of 92.5% after 1000 cycles for full cell and high capacity of 112.2 mAh g−1 for pouch cell. This study opens up new opportunities for the development of dendrite-free anodes for aqueous metal batteries.