To improve the electrolyte wettability and thermal stability of polypropylene (PP) separators, nano-SiO₂/poly(vinyl alcohol)-coated PP composite separators were prepared using a simple but efficient sol–gel and dip-coating method. The effects of the tetraethoxysilane (TEOS) dosage on the morphology, wettability, and thermal stability of the composite separators were investigated using Fourier-transform infrared spectroscopy, scanning electron microscopy, and contact-angle measurements. All the composite separators gave a smaller contact angle, higher electrolyte uptake, and lower thermal shrinkage compared with the PP separator, indicating enhanced wettability and thermal stability. Unlike the case for a traditional physical mixture, SiOC covalent bonds were formed in the coating layer. The composite separator with a TEOS dosage of 7.5 wt% had a unique porous structure combining hierarchical pores with interstitial voids, and gave the best wettability and thermal stability. The ionic conductivity of the composite separator containing 7.5 wt% TEOS was 1.26 mS/cm, which is much higher than that of the PP separator (0.74 mS/cm). The C-rate and cycling performances of batteries assembled with the composite separator containing 7.5 wt% TEOS were better than those of batteries containing PP separators.

为了提高聚丙烯（PP）隔膜的电解质润湿性和热稳定性，使用简单但有效的溶胶-凝胶和浸涂方法制备了纳米SiO ₂ /聚乙烯醇涂层的PP复合隔膜。使用傅里叶变换红外光谱，扫描电子显微镜和接触角测量研究了四乙氧基硅烷（TEOS）用量对复合隔膜的形态，润湿性和热稳定性的影响。与PP隔膜相比，所有复合隔膜的接触角更小，电解质吸收量更高，热收缩率更低，这表明可湿性和热稳定性得到了提高。与传统的物理混合物不同，Si O在涂层中形成C共价键。TEOS用量为7.5 wt％的复合隔膜具有独特的多孔结构，该多孔结构结合了分层孔隙和间隙空隙，并具有最佳的润湿性和热稳定性。包含7.5 wt％TEOS的复合隔板的离子电导率为1.26 mS / cm，远高于PP隔板的电导率（0.74 mS / cm）。用包含7.5 wt％TEOS的复合隔膜组装的电池的C速率和循环性能要好于使用PP隔膜的电池。