A Polyacrylamide-Based Zinc Sulfate Hydrogel Electrolyte Enhanced by Triethyl Phosphate toward Stable Zinc Ion Battery Anode.

Abstract

The problems associated with dendrite growth, hydrogen evolution reaction, and corrosion reaction on the zinc anode surface have hindered the commercial application of zinc-ion batteries (ZIBs). Herein, a crosslinked hydrogel electrolyte (zinc sulfate/polyacrylamide/triethyl phosphate hydrogel, denoted as ZS/TEP/H₂O GEL) is designed to stabilize the Zn anode interface and electrolyte, smooth Zn deposition and improve battery cycle life. The ZS/TEP/H₂O GEL electrolyte limits water molecule activity through a 3D network, thereby suppressing water-related side reactions and enhancing the stability of the anode. In addition, the TEP additive in ZS/TEP/H₂O GEL induces the Zn²⁺ to deposit preferentially along the (002) crystal plane and enables homogeneous zinc deposition. Ultimately, the Zn//Zn battery assembled with ZS/TEP/H₂O GEL can achieve an extremely long-cycle life exceeding 4000 h at 0.2 Ma cm^-2. Besides, the Zn//Cu half battery can be plated/stripped stably for more than 1000 cycles at a current density of 1 mA cm^-2. The Zn//NVO full battery with ZS/TEP/H₂O GEL electrolyte is able to maintain a relatively stable trend at a later stage. This work offers a reference for the exploration of commercialized hydrogel electrolytes with stable zinc anodes to realize long-life ZIBs.