Soaking-free and self-healing hydrogel for wearable zinc-ion batteries

The rapid expansion of wearable electronic market has boosted the requirement of flexible energy storage devices. Currently, challenges still exist in designing high-performance flexible batteries with high-safety and good mechanical durability. Herein, we develop a soaking-free and self-healing hydrogel electrolyte for advanced wearable Zn-ion batteries (ZIBs). During the hydrogel fabrication, Zn2+ ion is introduced as the cross-linking agent to trigger the double-network structure formation. Interestingly, Zn2+ can directly work as the charge carrier during battery operation by avoiding the traditional soaking process, which helps to address the Zn issues. After applying in the Zn/polyaniline (PANI) battery, this functional hydrogel guarantees a long lifespan of 2000 cycles under 3 A g−1 with a capacity retention of 94.6 %. Moreover, this hydrogel features an excellent self-repairability due to its supramolecular interactions, which enables its practicability. When assembling a Zn/PANI pouch cell, it maintains the stable energy outputs under harsh environments, such as pressing, folding, squeezing, twisting, piercing, and hammering. Our work provides guidance for constructing soaking-free and self-healing hydrogels for next-generation wearable Zn-based batteries.