Dual-Functional Asymmetric PDOL-Based Gel Polymer Electrolyte for High-Performance Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries are promising next-generation storages, benefiting from high theoretical energy density and low-cost. However, their practical application is limited by severe lithium polysulfides (LiPSs) shuttling and lithium dendrite formation, resulting in poor cycle life and safety risks. An in situ formed asymmetric gel polymer electrolyte (GPE), comprising PDOL-PSN on the cathode side and a PDOL-LLZO layer on the anode side, is developed to overcome these challenges. The PDOL-PSN layer effectively anchors LiPSs via Lewis acid-base interactions, while promoting uniform Li⁺ transport. Meanwhile, the PDOL-LLZO layer facilitates uniform Li⁺ deposition and promotes the formation of a robust, ion-conductive solid-electrolyte interphase (SEI). Molecular dynamics and density functional theory simulations provide further insight into the suppression mechanism of the shuttle effect, revealing strong interactions between functional groups and LiPSs. As a result, the asymmetric GPE based Li//Li symmetric cell achieves stable cycling for over 2200 h at 0.5 mA cm^-2/1 mAh cm^-2. Furthermore, the corresponding Li-S full cell exhibits a high initial discharge capacity of 1062.1 mAh g^-1 with 87.9% retention after 100 cycles at 0.2 C, and a coulombic efficiency higher than 96.6%. This work offers a viable strategy for designing multifunctional asymmetric electrolytes toward high-performance and durable Li-S batteries.