Electrospun Poly(Vinyl Alcohol)/ TiO 2 Nanofiber Membranes With Improved Wettability and Thermal Dimensional Stability for Lithium‐Ion Battery Separators

Electrospun poly(vinyl alcohol) (PVA)/titanium dioxide (TiO 2 ) nanofiber membranes with 0, 5, 10, and 15 wt% TiO 2 (relative to PVA) were prepared through a water‐based route and characterized for lithium‐ion battery separator applications. Their morphology, electrolyte wettability and uptake, thermal dimensional stability, and mechanical properties were evaluated. All membranes displayed nonwoven nanofiber structures, while FTIR spectra supported TiO 2 incorporation. Compared with a commercial polypropylene (PP) separator evaluated under identical conditions, the PVA/TiO 2 membranes exhibited greater apparent porosity (75.76%–80.72% vs. 41%), electrolyte uptake (303.23%–369.69% vs. 67%), and wettability (contact angles of 27°–47° vs. approximately 72°). PVTi10 showed the most balanced physicochemical properties, combining 80.72% apparent porosity, 369.69% electrolyte uptake, a 27° contact angle, 5.23% shrinkage after heating at 200°C for 30 min, and 8.91 MPa tensile stress. In preliminary NMC/graphite full‐cell testing at 1 A g −1 , the PVTi10‐based cell delivered approximately 189 mAh g −1 , compared with 128 mAh g −1 for the PP‐based cell. These results identify 10 wt% TiO 2 as the most balanced composition investigated, while separator‐specific ionic conductivity, Li + transference number, and long‐term cycling stability remain unmeasured.