Lamellar Regulation for Fast and Reversible Zinc-Ion Transport in Water-Rich Hydrogels for Aqueous Zinc-Ion Batteries

The trade-off between stability and efficiency has critically impeded the widespread applications of aqueous zinc-ion batteries (ZIBs). Hydrogel electrolytes typically require a high content of water to achieve desirable ionic conductivities, which still led to stability issues in ZIBs. Herein, a simple approach is proposed to simultaneously improve the Zinc-ion (Zn²⁺) transportation and stability of water-rich hydrogels for ZIBs by constructing lamellar regulation of lyotropic liquid crystals (LLCs). Lamellar water-rich hydrogels with a high liquid content of 82% are prepared by polymerization of acrylamide in lamellar LLC solutions, which were formed by self-assembly of amphiphilic sodium dodecyl sulfate (SDS) in ZnSO₄ solutions. The self-assembly of SDS regulates the ZnSO₄ solutions within the lamellar LLC nanostructures. The lamellar regulation enables fast and reversible Zn²⁺ transport in hydrogels and suppress the side reactions at Zn/hydrogel interfaces, which synergistically boost the efficiency and stability of ZIBs. The lamellar water-rich hydrogel electrolytes show superior charge/discharge capacities and robust cyclic performance in separator-free V₂O₅//Zn pouch cells comparing to corresponding conventional water-rich hydrogels and micellar water-rich hydrogels. The work here paves new way of introducing lamellar LLC nanostructures for developing high-performance hydrogel electrolytes for superior ZIBs.