In a previous Study, a lithium ion battery separator was coated with polymers synthesized from various ethylene glycol dimethacrylates to enhance its meltdown temperature. The meltdown temperature of the separator was increased to 155 degrees C when it was coated with polymer synthesized from diethylene glycol dimethacrylate (DEGDMA). In this study, a PE separator was coated with nanocomposites composed of DEGDMA polymer and silica nanoparticles for further enhancement of the meltdown temperature. Coatings with nanocomposites were prepared via two different methods: coating the separator by reacting a methanol solution containing DEGDMA and silica nanoparticles or coating the separator by reacting with a methanol solution containing water, DEGDMA, and tetraethylorthosilicate. The formation of nanocomposite on the separator was confirmed by FT-IR, EDS, and electron microscopy. Regardless of the coating method, an increase in the meltdown temperature with a decrease in the air permeability was observed with the nanocomposite coating. The meltdown temperature of the separator was increased to 170 degrees C with all acceptable reduction in the air permeability when the separator was coated with composite using the latter method.