Electric Field Propelled Anion‐Type Solvation Structure Reconstruction With Accelerated Kinetics for Low‐Temperature Zinc Metal Batteries

Abstract

ABSTRACT Organic‐rich eutectic electrolytes, which have been prevalent to address the electrolyte freezing and Zn dendrite growth challenges for low‐temperature aqueous zinc‐based batteries, suffer from sluggish Zn 2+ desolvation kinetics and mass transport. Here, we introduce aprotic acetone as a cosolvent to improve the performance of aqueous Zn(BF 4 ) 2 ‐based electrolyte under cold environments. Leveraging dynamic keto‐enol tautomerism in the primary solvation sheath of Zn 2+ propelled by the electrical double layer electric field, an anion‐type solvation structure is established, which shortens the Zn 2+ desolvation path with accelerated kinetics and constructs a tough and tight interface with a gradient organic‐inorganic configuration, eventually enabling uniform Zn deposition at low temperatures. As a result, Zn||Zn symmetric cells sustain for 7500 h at 1 mA·cm −2 and over 1200 h with 34.2 % DOD at 10 mA·cm −2 under −40°C. Pouch‐cell properties are demonstrated by matching a PEDOT‐V 2 O 5 cathode, which harvests a high capacity of 150 mAh over 210 cycles under practical conditions (N/P = 4.33 and E/C = 6.0 µL mg −1 ) and holds approaching 100 % capacity retention at −40°C. This work provides an effective strategy toward industrializing practical cold‐resistant zinc‐based batteries via modulating the electrolyte structure.