High‐performance nano‐TiO2@polyvinylidene fluoride composite separators prepared by electrospinning for safe lithium‐ion battery

Abstract

AbstractTraditional polyolefin separators cannot guarantee safety for lithium‐ion batteries at high temperature due to their low melting point, especially for high power discharge. Therefore, it is imperative to develop separators with excellent thermal stability. In this paper, we have prepared TiO2 modified PVDF composite separators by electrospinning. When compared with commercial PE separators, this kind of composite separators show superior thermal stability at 160°C. In addition, it is found that the 0.5‐TiO2@PVDF separator exhibits excellent flame retardant and optimal tension strength. Meanwhile, the 0.5‐TiO2@PVDF separator exhibits ideal liquid electrolyte storage capacity, which improves the ionic conductivity (0.68 mS cm−1). As a result, the LiCoO2||Li cells with 0.5‐TiO2@PVDF separator have high discharge capacity retention rate at a current density of 1 C (300 cycles) and excellent rate performance (1.75 mAh at 5 C). In short, nano‐TiO2 modified PVDF separator has a great application prospect in high‐performance and high‐safety lithium‐ion batteries.