Sustainable APTES‐Modified Nano‐TiO ₂ /PVA Composite Nanofibrous Separators for Thermally Stable Lithium‐Ion Battery

Abstract Commercial separators face several significant challenges that must be addressed before they can be used effectively in high‐energy‐density batteries. These issues include low porosity, poor electrolyte wettability, and inadequate dimensional stability. To address these challenges, 3‐aminopropyltriethoxysilane (APTES)‐modified nano‐TiO ₂ (MNT) with improved dispersion and interfacial compatibility, an isocyanate‐based cross‐linker and poly(vinyl alcohol) (PVA) as a spinning solution component are used to prepare the electrospun nanofibrous separator in this work. The obtained MNT/PVA separator demonstrates superior performance, including high mechanical strength (33.2 MPa), excellent thermal dimension stability (with no shrinkage at 200 °C), high porosity (82.5%), substantial electrolyte uptake (566.1%), and outstanding ionic conductivity (1.54 mS cm ⁻¹ ). Moreover, when applied in button cell batteries, the MNT/PVA separator retains more than 88.3% of its initial capacity (137.9 mAh g ⁻¹ ) after 100 cycles at 0.5C. This performance surpasses that of conventional PVA and Celgard separators, suggesting that the MNT/PVA separator has a great potential to replace commercial counterparts in advanced lithium‐ion batteries.