Sol-gel deposition of silica nanospheres onto polymeric separators for improved performance of Li-ion batteries

The left figures show the top-view FE-SEM images of different polymeric separators: (a) U, (b) S1, (c) S2, and (d) S3, which represent the amount of tetraethoxysilane of 0, 1.5, 3.0, and 6.0 ml in the colloidal suspension, respectively. The right figures illustrate thermal shrinkage of bare and silica-coated separators, where the separators are subjected to heat treatment at 60-180°C for 10 min. It is seen that the silica-coated separators exhibit a reduced thermal shrinkage as compared to bare separator within the entire temperature range. This reveals that the sol-gel deposition of SiO2 nanospheres offers an efficient thermal insulation technique in enhancing thermal resistance of separators.201