Bioinspired Vascular Bundle Structured Nanocellulose/PVDF-HFP Composite Membranes for Efficient Ion Transport and Stable All-Solid-State Lithium BatteriesOA

In-situ polymerization of solid-state polymer electrolytes is a promising approach for achieving mass production of all-solid-state batteries.However,inferior ionic conductivity and separator infiltration limit practical applications.Inspired by the nutrient-transporting vascular bundles in plants,a biomimetic fluorinated nanocellulose/PVDF-HFP porous composite membrane of stacked parallel nanocellulose bundles wrapped by PVDF-HFP sheaths is designed and prepared.The nanocellulose bundles assembled of fluorinated cellulose nanocrystals and cellulose nanofibers through shear-induced alignment create low-curvature ion transport channels,while the PVDF-HFP sheath facilitates lithium salt dissociation and reinforces structural stability.Benefiting from this bundle-sheath structure,the composite membrane exhibits excellent ionic conductivity,stability,and electrolyte wettability.The polymer electrolyte prepared with this composite membrane has a high ionic conductivity of 2.46×10^(-4)S cm^(-1)(30℃),an electrochemical stability window(5.3 V),and cycle stability.Consequently,LiLFP cells can retain a superior capacity of 77.48% after 1000 cycles at 1 C,and LiNCM811 cells can maintain 83.94%capacity after 300 cycles at 0.1 C.Moreover,pouch cells can withstand temperatures up to 130℃ without thermal runaway.This biomimetic strategy provides a promising pathway to advance cellulose separators for high-performance all-solid-state batteries.