Covalently-Bonded Poly(vinyl alcohol)-Silica Composite Nanofiber Separator with Enhanced Wettability and Thermal Stability for Lithium-Ion Battery

Covalently-bonded poly(vinyl alcohol)-silica (PVA-SiO2) composite nanofiber membranes are fabricated via sol-gel electrospinning and their physical and electrochemical properties are investigated for application as separators in lithium-ion batteries (LIBs). Experimental results demonstrate the PVA-SiO2 membranes possess a unique three-dimensional interconnected porous structure and display higher porosity (73%), better electrolyte affinity, higher electrolyte uptake (405%) and lower thermal shrinkage compared to commercial polypropylene (PP) membranes. In addition, batteries using PVA-SiO2 composite nanofiber membranes as separators exhibit enhanced ionic conductivity (1.81 mS cm(-1)), superior cycling stability and C-rate performance than those using PP separators. These findings reveal that the PVA-SiO2 composite nanofiber membrane might be a promising alternative to commercial polyolefin separator for high performance LIBs.