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

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/H 2 O GEL) is designed to stabilize the Zn anode interface and electrolyte, smooth Zn deposition and improve battery cycle life. The ZS/TEP/H 2 O 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/H 2 O GEL induces the Zn 2+ to deposit preferentially along the (002) crystal plane and enables homogeneous zinc deposition. Ultimately, the Zn//Zn battery assembled with ZS/TEP/H 2 O 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/H 2 O 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. Graphical In this work, a triethyl phosphate reinforced polyacrylamide-based hydrogel electrolyte is designed and prepared and used for zinc ion batteries. The long-cycle stability of Zn//Zn symmetric batteries, reversibility, and Zn//NVO full battery performance assembled with this electrolyte are evaluated. The effect of this electrolyte on Zn deposition behavior is also studied.