Fundamental study on Zn corrosion and dendrite growth in gel electrolyte towards advanced wearable Zn-ion battery

Wearable Zinc-ion batteries (ZIBs) are considered a promising energy storage device due to their superiorities in both safety and cost. However, the Zn reversibility in wearable ZIBs has not been yet studied. Here, our study reveals that gel electrolytes can suppress the dendrite growth to prolong the Zn lifespan, but they cannot address corrosion reactions, resulting in poor reversibility. To further enhance the mechanical properties of gel electrolyte and Zn reversibility, a functional double-network hydrogel electrolyte (FDHE) is designed, in which the unique poly-2-Acrylamido-2-methylpropanesulfonic/polyacrylamide (PAMPS/PAAM) structure provides a robust mechanical property. Meanwhile, the additive of dimethyl sulfoxide as an H-acceptor and solvation regulator is added during the synthesis of FDHE, which not only inhibits side reactions by reducing the activity of free water but also diminishes the de-solvation energy barrier by regulating the Zn2+ solvation structure. Consequently, the Zn electrode in FDHE-based Zn coin-cell displays excellent reversibility even under −10 °C. After assembling wearable ZIBs, outstanding performance is also achieved under different bending states. Our study provides an in-depth understanding of Zn behavior in gel electrolytes and paves the way to design next-generation wearable ZIBs.