Möbius Solvation Structure for Zinc-Ion Batteries

Abstract

Zinc-ion batteries (ZIBs) have promising prospects in energy storage field, but the water molecules in aqueous electrolytes significantly compromise the stability of the anode and cathode interfaces and hinder the low-temperature performance. Herein, water-in-oil type Möbius polarity topological solvation composed of oil, water, and amphiphilic salt are first-ever pioneered, forming the surfactant-free microemulsion electrolyte (SFMEE). This water-in-oil type Möbius solvation structure, characterized by its distinct inner and outer layers and a polarity inversion feature, successfully connects the non-polar phase with the polar phase, eliminating the need for surfactants to reduce costs and system complexity. The amphiphilic anion of salt creates a polarity singularity and stabilizes the polarity-reversed encapsulation. The outer oil layer disrupts the cohesive polarity network of water and constructs a polarity-reversed cage to restrict water. A series of SFMEE combinations are investigated and then directly applied to ZIBs, confirming excellent universality and durability of this design. The Zn||NVO (NaV₃O₈·1.5H₂O) cells using SFMEE can stably cycle for 4000 cycles with a capacity of 125 mAh g⁻¹ and 86.8% capacity retention. This discovery of Möbius solvation structure unlock unprecedented levels of electrolyte design and illuminate the development of next-generation high-performance energy storage systems.