Modified Regenerated Cellulose Membranes via Interfacial Grafting Engineering for Lithium Metal Batteries

In this work, regenerated cellulose (RC) membranes with surface-grafted poly(Nvinylpyrrolidone) (PVP) side chains are prepared via an interfacial grafting engineering strategy.A xanthate-based reversible addition-fragmentation chain-transfer (RAFT) agent is covalently immobilized on the RC fiber surface, followed by surface-initiated RAFT polymerization to obtain a series of RC-g-PVP membranes.The introduction of PVP chains provides abundant carbonyl groups on the membrane surface, which can serve as Li⁺ coordination sites and alter the local ionic environment.Compared with pristine RC membranes, RC-g-PVP-3 exhibits improved rate capability up to 3C-rate and enhanced cycling performance, while showing higher discharge capacities than commercial polyethylene (PE) and polypropylene (PP) separators across the tested Crates.Notably, pronounced grafting-level-dependent electrochemical behavior is observed, reflecting a delicate balance between interfacial chemical regulation and ion transport.Post-cycling morphological characterization reveals a relatively smooth and compact Li metal anode surface in cells using RC-g-PVP-3.This work demonstrates that applying interfacial grafting engineering to regenerated cellulose membranes provides a viable route to tune ion transport in Li metal batteries.