Breaking the Ice: Hofmeister Effect-Inspired Hydrogen Bond Network Reconstruction in Hydrogel Electrolytes for...

Gel electrolytes have emerged as a promising solution for enhancing the performance of zinc-ion batteries (ZIBs), particularly in flexible devices. However, they face challenges such as low-temperature inefficiency, constrained ionic conductivity, and poor mechanical strength. To address these issues, this study presents a novel PAMCD gel electrolyte with tunable freezing point and mechanical properties for ZIBs, blending the high ionic conductivity of polyacrylamide with the anion interaction capability of β-cyclodextrin. Leveraging the Hofmeister effect, the chaotropic anions of ClO₄ ^- are integrated to weaken hydrogen bonds, enhancing the mechanical and anti-freezing properties. The chaotropic salt disrupts the hydrogen bond network within water molecules, increasing weaker bonds and forming contact ion pairs, while polyacrylamide chains bind water molecules, further destabilizing hydrogen bonds. These changes improve Zn²⁺ ion mobility, mechanical resilience, and reduce the freezing point, significantly boosting ZIB performance. Consequently, the Zn-Zn symmetric cells achieve remarkable lifespans over 5290 hours at 0.5 mA cm^-2 and 1960 hours at 5 mA cm^-2, and the Zn-polyaniline full batteries maintain a high capacity of 100.8 mAh g^-1 at 2 A g^-1, even at -40 °C, over 7600 cycles, showcasing superior cyclability and rate performance.