A MOF-Derivative Decorated Hierarchical Porous Host Enabling Ultrahigh Rates and Superior Long-Term Cycling of Dendrite-Free Zn Metal Anodes.

Abstract

Aqueous Zn metal batteries have attracted much attention due to their high intrinsic capacity, high safety, and low cost. Nevertheless, uncontrollable dendrite growth and adverse side reactions of Zn anodes seriously hinder their further application. Herein, a three-dimensional (3D) porous graphene-carbon nanotubes scaffold decorated with metal-organic framework derived ZnO/C nanoparticles (3D-ZGC) is fabricated as the host for dendrite-free Zn-metal composite anodes. The zincophilic ZnO/C nanoparticles act as preferred deposition sites with low nucleation barriers to induce homogeneous Zn deposition. The mechanically robust 3D scaffold with high conductivity not only suppresses the formation of dendritic Zn by reducing the local current density and homogenizing Zn²⁺ ion flux, but also inhibits volume changes during the long-term plating/stripping process. As a result, the 3D-ZGC composite anodes afford unprecedented Zn plating-stripping stability at an ultrahigh current density of 20 mA cm^-2 for 1500 cycles with low overpotential (<65 mV) when used in a symmetric cell. When coupled with MnO₂ cathodes, the assembled Zn@3D-ZGC//MnO₂ full batteries deliver an enhanced cycling stability for up to 6000 cycles at 2000 mA g^-1 , demonstrating the potential of the 3D-ZGC composite anode for advanced Zn metal batteries.