Restructuring Hydrogen Bond Networks in Polyacrylamide Hydrogels via Trehalose Additives for Wide-Temperature-Range Zn-Ion Batteries

Aqueous Zn-ion batteries utilizing moldable gel electrolytes are expected to meet power requirements for wearable devices because of their inherent safety and energy output. Nevertheless, comprehensive modulation over the mechanical robustness, water retention capability, and electrode–electrolyte interface stability remains at a nascent stage. Drawing inspiration from the naturally cryoprotective and hygroscopic properties of trehalose, we herein devise a strategy by incorporating trehalose into polyacrylamide hydrogel electrolytes, targeting the construction of wearable Zn-ion batteries. The optimized hydrogel electrolyte demonstrates low-temperature adaptability (−15 °C), high-temperature stability (50 °C), and water retention capability while helping to suppress dendrite growth and parasitic reactions. Theoretical calculations and electrochemical characterizations reveal that trehalose modifies the Zn-ion solvation structure and optimizes the electrode–electrolyte interface. The thus-fabricated Zn-ion batteries exhibit favorable electrochemical performances in a wide-temperature range, achieving a capacity retention of 87.2% after 2000 cycles at 5 A g^–1. The assembled pouch cell could also be sustained for more than 500 cycles. Moreover, the integration of our Zn-ion batteries with Si solar cells to construct a wearable solar-charging system enables an energy conversion efficiency exceeding 10%.