Effect of sol–gel synthesized Al0.1Zr0.9O1.95 nanoparticles and PVP on PVDF-based separators in lithium-ion battery performance: The RSM study

Abstract

In this study, the simultaneous effects of Al0.1Zr0.9O1.95 nanoparticles (NPs) and polyvinyl pyrrolidone (PVP) on the ion-conductivity of poly (vinylidene fluoride) (PVDF)-based separator were investigated. The ion-conductivity of PVDF/PVP/Al0.1Zr0.9O1.95 was optimized by using response surface methodology combined with central composite design. The Al0.1Zr0.9O1.95 as a nanofiller was synthesized by the sol–gel auto-combustion method. The PVDF/PVP/Al0.1Zr0.9O1.95 separators were prepared by phase inversion method. The properties and structure of optimal separator were compared with pure PVDF as a reference. The ion-conductivity of optimal separator has increased by 30.73% related to pure PVDF separator. The porosity and electrolyte uptakes of optimal separator were increased from 41% to 57% and from 246% to 384%, respectively, compared to the pure PVDF separator. Moreover, the optimal separator has a better anti-thermal shrinkage than pure PVDF separator over a wide temperature range. It is found that optimal separator (4.6 V) has a higher electrochemical stability window than pure PVDF separator (3.75 V). Also, compared with the pure PVDF separator, the optimal separator has a better discharge capacity. NPs were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy. The separators were investigated by XRD, surface and cross-section SEM, atomic force microscopy, and water contact angle.