In Situ Formation of 3D ZIF-8/MXene Composite Coating for High-Performance Zinc-Iodine Batteries

Abstract

Aqueous Zn batteries have garnered a great deal of attention owing to environmental benefits, intrinsic safety, and cost-effectiveness. However, the commercial viability of these batteries is hindered by Zn anode issues, including dendrite formation and side reactions. Herein, the authors modulate the deposition behavior of Zn²⁺ ions through a 3D ZIF-8@MXene (Z@M) composite coating. The Z@M coating can effectively reduce the contact area with the electrolyte, inhibiting the hydrogen evolution reaction and Zn corrosion. Notably, theoretical calculations and in situ experimental observations of Zn deposition reveal that the dual coordination mechanism of MXene and ZIF-8 significantly improves the adsorption energy of Zn atoms. This improved capacity to capture Zn²⁺ ions will promote the desolvation of hydrated Zn²⁺ ions, resulting in a dendrite-free deposition process. Therefore, in a symmetry cell, the Z@M-Zn anode demonstrates an impressive cycle life of 1050 h at 1 mA cm⁻². When applies in an aqueous Zn-I₂ battery, the Z@M-Zn anode demonstrates a remarkable lifespan of over 2400 cycles at 5 C. This work provides a straightforward approach to designing reversible Zn anode, offering promising potential for broader applications across various metal-based anode systems.