A Facile Strategy for Constructing High‐Performance Polymer Electrolytes via Anion Modification and Click Chemistry for Rechargeable Magnesium Batteries

Abstract Polymer electrolytes play a crucial role in advancing rechargeable magnesium batteries (RMBs) owing to their exceptional characteristics, including high flexibility, superior interface compatibility, broad electrochemical stability window, and enhanced safety features. Despite these advantages, research in this domain remains nascent, plagued by single preparation approaches and challenges associated with the compatibility between polymer electrolytes and Mg metal anode. In this study, we present a novel synthesis strategy to fabricate a glycerol α,α′‐diallyl ether‐3,6‐dioxa‐1,8‐octanedithiol‐based composite gel polymer electrolyte supported by glass fiber substrate (GDT@GF CGPE) through anion modification and thiol‐ene click chemistry polymerization. The developed route exhibits novelty and high efficiency, leading to the production of GDT@GF CGPEs featuring exceptional mechanical properties, heightened ionic conductivity, elevated Mg 2+ transference number, and commendable compatibility with Mg anode. The assembled modified Mo 6 S 8 ||GDT@GF||Mg cells exhibit outstanding performance across a wide temperature range and address critical safety concerns, showcasing the potential for applications under extreme conditions. Our innovative preparation strategy offers a promising avenue for the advancement of polymer electrolytes in high‐performance rechargeable magnesium batteries, while also opens up possibilities for future large‐scale applications and the development of flexible electronic devices.