Molecular crowding effect synergies ice breaking: A Cryogenic revival prescription for aqueous Zn-ion batteries

Aqueous Zn-ion batteries have been widely concerned for their high ionic conductivity and intrinsic safety. However, solvated water easily induces HER to deteriorate Zn anode interface and has poor performance at low temperatures. Here, formamide (FA) and D-xylose (DX) synergically induce a molecular crowding effect that increases Zn²⁺ kinetics and decreases the freezing point. FA as a ‘chain’ is mainly used to regulate the solvation structure of Zn²⁺ and DX as a ‘bridge’ is mainly used to destroy the hydrogen bond network of water. Therefore, the multiple Zn²⁺ solvation configurations present in FD can effectively inhibit the side reactions and reduce its freezing point to -51 °C. The Zn∣∣Zn battery can operate for more than 3000 h at -35 °C (0.5 mA cm^-2). The average CE of Zn∣∣Cu battery after 3000 cycles is close to 100 %. The capacity retention rate of Zn∣∣PANI battery is 80 % after 3000 cycles at 30 °C (3 A g^-1) and 91 % after 750 cycles at -35 °C (0.1 A g^-1). This study provides a three-in-one modification strategy of ‘solvation structure - deposition kinetics - interface stability’ and provides practical insights for the application of AZIBs at extremely low temperatures.