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

Abstract Covalently‐bonded poly(vinyl alcohol)‐silica (PVA‐SiO 2 ) 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‐SiO 2 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‐SiO 2 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‐SiO 2 composite nanofiber membrane might be a promising alternative to commercial polyolefin separator for high performance LIBs.