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

Abstract 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.