Lamellar lyotropic liquid crystals enabled beyond-liquid electrolytes for advanced Zn-ion batteries

Abstract

Developing solid-state aqueous electrolytes combining liquid-like conducting performance, wide voltage windows, and anti-dendrite growth are satisfactory for efficient and durable Zn-ion batteries (ZIBs). Herein lamellar lyotropic liquid crystals (LLCs) are designed and prepared as solid-state electrolytes with comprehensive performance overwhelming to corresponding aqueous liquid electrolytes for ZIBs. The lamellar LLCs are simply prepared by nano-segregation of amphiphilic sodium dodecyl sulfate (SDS) in 2 M ZnSO₄ aqueous solutions. SDS shows good compatibility in forming lamellar LLCs even with a high content of 500 wt% ZnSO₄ solutions. The lamellar assembly constructs broadened liquid conducting pathways for efficient Zn-ion transport, which boosts ion conductivity of the lamellar electrolytes surpassing corresponding ZnSO₄ solutions. Also, the lamellar nanostructures of LLC electrolytes enable higher voltage windows (2.5 V) and anti-dendrite growth performance. The lamellar electrolytes show superior energy conversion efficiency and durability comparing to the ZnSO₄ solution electrolytes in Zn/V₂O₅ based ZIBs, and possess robust viscoelasticity and interfacial contact for flexible ZIB applications to rival commonly-applied hydrogel electrolytes. The work here demonstrates a new branch for developing aqueous solid-state electrolytes with beyond-liquid performance to supersede traditional liquid electrolytes for efficient and durable ZIBs.