In Situ Polymerization Bi‐Functional Gel Polymer Electrolyte for High Performance Quasi‐Solid‐State Lithium−Sulfur Batteries

Abstract Lithium–sulfur (Li–S) batteries are expected to be the next‐generation energy storage system due to the ultrahigh theoretical energy density and low cost. However, the notorious shuttle effect of higher‐order polysulfides and the uncontrollable lithium dendrite growth are the two biggest challenges for commercially viable Li–S batteries. Herein, these two main challenges are solved by in situ polymerization of bi‐functional gel polymer electrolyte (GPE). The initiator (SiCl 4 ) not only drives the polymerization of 1,3‐dioxolane (DOL) but also induces the construction of a hybrid solid electrolyte interphase (SEI) with inorganic‐rich compositions on the Li anode. In addition, diatomaceous earth (DE) is added and anchored in the GPE to obtain PDOL‐SiCl 4 ‐DE electrolyte through in situ polymerization. Combined with density functional theory (DFT) calculations, the hybrid SEI provides abundant adsorption sites for the deposition of Li + , inhibiting the growth of lithium dendrites. Meanwhile, the shuttle effect is greatly alleviated due to the strong adsorption capacity of DE toward lithium polysulfides. Therefore, the Li/Li symmetric cell and Li–S full cell assembled with PDOL‐SiCl 4 ‐DE exhibit excellent cycling stability. This study offers a valuable reference for the development of high performance and safe Li–S batteries.