Reconstructing Solvation and Interface Dynamics for High-Performance Hydrogel Polymer Zn-S Batteries

In this work, an agarose-polyacrylamide hydrogel electrolyte (APE) with an interpenetrating and hierarchically porous network is introduced to reconstruct solvation and interface dynamics for a high-performance Zn-S batteries. This structure results in a high ionic conductivity of 42.1 mS cm^-1 and a Zn²⁺ transference number of 0.64. Molecular dynamics reveal that most H₂O and SO₄ ^2- are excluded from the outer Helmholtz plane, forming an optimized electric double layer on Zn surface. Consequently, a prolonged 1200 h Zn plating/stripping behavior is obtained with 1 mAh cm^-2 at 1 mA cm^-2, and a high Zn plating of 20 mAh cm^-2 at 5 mA cm^-2. Furthermore, APE modulates the nucleation mode of ZnS, converting the originally sluggish and non-uniform progressive nucleation into a rapid and uniform instantaneous nucleation. As a result, this hydrogel Zn-S batteries deliver a capacity of 895 mAh g^-1 and 91% capacity retention within 300 cycles at 5 A g^-1.