Heat-Resistant\nCovalent Organic Framework (COF) PVA-Hybridized\nGel Electrolyte for the Preparation of Dendrite-Free Zinc-Ion Batteries

High-performance zinc-ion batteries (ZIBs) have attracted\na great\ndeal of attention due to their high theoretical capacity and high\nlevel of safety. Herein, we propose a covalent organic framework (COF)\nhybrid poly(vinyl alcohol) (PVA)-based gel electrolyte, which can\ninduce the uniform deposition of Zn<sup>2+</sup> and achieve dendrite-free\nformation. By grafting sulfonic acid groups on the surface of COFs\nto absorb Zn<sup>2+</sup>, we can strengthen the interaction between\nstrong ions and dipoles in the electrolyte, improve the ionic conductivity,\nand achieve stable Zn<sup>2+</sup> electroplating and stripping. Due\nto the good thermal stability of the COF material itself, the gel\nelectrolyte hybrid with the PVA hydrogel shows high mechanical strength\nand good heat resistance and is capable of stable cycling for >1000\nh at 50 °C, with a capacity retention rate of ≤75%. This\nstudy provides a new approach for developing high-temperature-resistant\nand highly stable dendrite-free ZIBs.