Carbonate-Assisted Chaotropic Electrolyte for Zinc Ion Battery with Wide Temperature Operation

The chaotropic salt electrolyte (CSE) has become an effective strategy to activate low-temperature aqueous zinc-ion batteries. However, the Zn battery performance has been largely compromised due to the side reaction of active water molecules in CSE. Herein we design a Zn(BF4)2 in a propylene carbonate–water cosolvent electrolyte that facilitates the zinc plating/stripping in a wide temperature range (−40 to 60 °C). Theoretical and experimental results demonstrate the dual effect of propylene carbonate on regulating the hydrogen bond network and reshaping the Zn2+ solvation structure, bringing the antifreezing property and smooth Zn plating/stripping. Consequently, at −20 °C, the Cu//Zn asymmetric cell can achieve stable cycling for over 4000 h at 0.5 mAh cm–2. At −40 °C, the Zn//tetrachlorobenzoquinone full battery can deliver a reversible specific capacity of 77.9 mAh g–1 after 700 cycles. This work presents an effective strategy for the development of high-performance ZIBs in a wide temperature range.