Regulating the Coordination Environment of HO in Hydrogel Electrolyte for a High-Environment-Adaptable and High-Stability Flexible Zn Devices.

Aqueous zinc-ion batteries are promising candidates as stationary storage systems for power-grid applications due to their high safety and low cost. The practical implementation of Zn-ion batteries currently still faces formidable challenges because of Zn dendrite growth, hydrogen evolution, and inadequate environmental adaptability. Herein, to address these challenges, a strategy of regulation of water molecules coordination in electrolyte is proposed via developing a cross-linked hydrophilic hydrogel polymer electrolyte. Within this system, the continuous hydrogen bond among HO molecules is disrupted and the isolated HO molecules are strongly bound with a polymeric matrix comprised of polyacrylamide, carboxymethyl cellulose, and ethylene glycol, which can restrain the activity of HO molecules, thus effectively alleviating Zn dendrite growth and hydrogen evolution and enhancing the anti-freezing ability. With this electrolyte, the Zn||Cu cell presents a high coulombic efficiency of 99.4% over 900 cycles and Zn||Zn symmetric cell exhibits high cycling stability, maintaining plating/stripping for over 1,700 h. Moreover, the assembled Zn||PANI device also demonstrates outstanding electrochemical performance over a wide-temperature range, including a long cycling life over 14,120 cycles at room temperature and an ultralong cycling surpassing 30,000 cycles even at - 40 °C. This showcases the manipulation of water coordination chemistry for advanced, highly adaptable batteries.