Molecular Crowding Agent Modified Polyanionic Gel Electrolyte for Zinc Ion Batteries Operating at 100 °C

Abstract Aqueous zinc‐ion batteries (AZIBs) attract attention due to their safety and high specific capacity. However, their practical applications are constrained by Zn anode corrosion, dendritic growth, and poor high‐temperature adaptability induced by a strong hydrogen‐bond network in aqueous electrolytes. In this work, a dual network polyanionic gel electrolyte (denoted as PAM‐PAMPS‐10PD) is developed capable of withstanding high temperatures (100 °C) by in situ polymerization. The abundant anionic groups in the gel electrolyte greatly improve Zn²⁺ transport and inducing uniform deposition of Zn²⁺. Then the addition of the high‐boiling molecular crowding agent 1,5‐pentanediol (PD) can inhibit the water activity by enhancing hydrogen bonding with H₂O and changing the solvation structure of Zn²⁺ to inhibit Zn anode corrosion. As a result, the symmetric battery using the PAM‐PAMPS‐10PD gel electrolyte can be stably cycled for at least 500 h at 100 °C and 0.5 mA cm⁻²/0.5 mAh cm⁻², realizing dendrite‐free zinc anodes at high temperatures. Moreover, the Zn–AC full battery has a capacity retention of 47.8% after 3000 cycles at 100 °C and 4 mA cm⁻². This study provides a beneficial reference for the design of high‐performance high‐temperature gel electrolytes and establishes a solid foundation for the practical application of AZIBs.