Lamellar lyotropic liquid crystal electrolytes based on a non-ionic surfactant for durable aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) are promising for large-scale energy storage owing to their intrinsic safety and low cost. However, their practical application is hindered by unstable Zn deposition and limited durability. Herein, lamellar lyotropic liquid crystal (LLC) electrolytes are developed through self-assembly of the non-ionic surfactant Brij®58 in aqueous Zn(OTf)₂ solution. The non-ionic surfactant Brij®58 is chosen to construct lamellar nanostructures without forming direct interactions with Zn²⁺ ions, which can reveal the role of nanostructures in aqueous electrolytes. Self-assembled lamellar nanostructures effectively regulate Zn²⁺ transport and redistribute the ion flux at the Zn/electrolyte interface, which promote Zn²⁺ conduction and homogenize Zn deposition. Benefiting from the lamellar regulation, the LLC electrolyte exhibits an ionic conductivity of 79 mS cm^-1, which is higher than that of Zn(OTf)₂ solution, as well as enables stable Zn plating/stripping with excellent interfacial stability for over 1000 h. When applied to Zn/V₂O₅ pouch cells, the LLC electrolyte delivers much enhanced cycling durability compared to the conventional Zn(OTf)₂ solution electrolyte, and it sustains stable operation for over 1600 charge-discharge cycles. This work demonstrates that only lamellar nanostructures in aqueous electrolytes can provide an effective strategy for balancing ion-transport efficiency and interfacial stability, which offers a viable platform for developing safe and durable AZIBs.