Constructing 3D Crosslinked Macromolecular Networks as a Highly Efficient Interface Layer for Ultra-Stable Zn Metal Anodes

Abstract

Aqueous zinc ion batteries (AZIBs) are experiencing rapid development due to their high theoretical capacity, abundant zinc resources, and intrinsic safety. However, the progress of AZIBs is hindered by uncontrollable parasitic reactions and excessive dendrite growth, which compromise the durability and effective utilization of zinc metal anodes. To address these challenges, the study has constructed a 3D crosslinked macromolecular network composed of zinc ion-bonded potato starch (StZ) as an interface layer on Zn foil (StZ-Zn) to inhibit hydrogen evolution, regulate Zn²⁺ flux, and ensure uniform Zn deposition. Density functional theory calculations, molecular dynamics simulations, COMSOL Multiphysics simulations, and in situ Raman spectra demonstrate that the 3D StZ interface layer facilitates Zn²⁺ desolvation by restructuring the solvation shells. This process reduces the concentration of H₂O at the anode, thereby inhibiting the hydrogen evolution reaction. Consequently, Zn²⁺ transport is more efficient, promoting a homogeneous Zn²⁺ flux and enabling dendrite-free Zn deposition. As a result, StZ-Zn||StZ-Zn symmetric cell delivers a superb lifespan of 4800 h at the current density of 5 mA cm⁻², and the corresponding cumulative capacity is as high as 12000 mAh cm⁻². Notably, StZ-Zn||NaV₃O₈·1.5H₂O full cell can stably operate for 2500 cycles at 5 A g⁻¹ with an outstanding capacity retention of 92%.