Modulating the Electrolyte Inner Solvation Structure via Low Polarity Co‐solvent for Low‐Temperature Aqueous Zinc‐Ion Batteries

Abstract

Aqueous zinc‐ion batteries are regarded as the promising candidates for large‐scale energy storage systems owing to low cost and high safety; however, their applications are restricted by their poor low‐temperature performance. Herein, a low‐temperature electrolyte for low‐temperature aqueous zinc‐ion batteries is designed by introducing low‐polarity diglyme into an aqueous solution of Zn(ClO4)2. The diglyme disrupts the hydrogen‐bonding network of water and lowers the freezing point of the electrolyte to −105 °C. The designed electrolyte achieves ionic conductivity up to 16.18 mS cm−1 at −45 °C. The diglyme and ClO4− reconfigure the solvated structure of Zn2+, which is more favorable for the desolvation of Zn2+ at low temperatures. In addition, the diglyme effectively suppresses the dendrites, hydrogen evolution reaction, and by‐products of the zinc anode, improving the cycle stability of the battery. At −20 °C, a Zn||Zn symmetrical cell is cycled for 5200 h at 1 mA cm−2 and 1 mA h cm−2, and a Zn||polyaniline battery achieves an ultra‐long cycle life of 10 000 times. This study sheds light on the future design of electrolytes with high ionic conductivity and easy desolvation at low temperatures for rechargeable batteries.