Sustainable Lignin‐Derived Cross‐Linked Graft Polymers as Electrolyte and Binder Materials for Lithium Metal Batteries

This study concerns the development of a well-defined synthetic route to obtain lignin-derived multifunctional graft polymers by simple chemical modification and atom-transfer radical polymerization. By grafting ion-conducting and cross-linkable moieties onto the lignin, star-shaped functional polymers are prepared. Upon cross-linking under ultraviolet light irradiation, the resulting polymer network exhibits mechanical stability even at high temperature, whereas the chain mobility is maintained despite the cross-linked structure. Their use as solid polymer electrolytes (SPEs) and binders for all-solid-state lithium metal batteries (LMBs) is also evaluated. The lignin-derived graft polymers provide a facile ion conduction pathway and also efficiently suppress lithium dendrite growth during cycling, thereby attaining excellent cycling performance for the LMB cell compared to that with a conventional liquid electrolyte-Celgard system.