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

Abstract This work presents an efficient sol–gel method to coat SiO 2 nanopheres onto tri-layered polymeric separators for Li-ion batteries, consisting of Li 4 Ti 5 O 12 (LTO) anode/Li cathode. The surface density of silica nanospheres with diameter of 300–500 nm is chosen as controlling factor in affecting the electrochemical performance and thermal stability of Li-ion batteries. The SiO 2 deposition on the polymeric separators exhibits not only an enhanced thermal and dimensional stability but also an improved rate capability and inner resistance. The excellent performance originates from the formation of robust skeleton to stabilize the separators, allowing a superior insulation and mass transport barrier against volatile compounds generated during thermal decomposition process. An appropriate amount of SiO 2 nanospheres still features a highly porous structure, imparting favorable liquid wettability, high mass uptake of electrolyte, and superior ionic conductivity. Accordingly, the sol–gel deposition method is believed to attract interests for applications in Li-ion batteries due to its simplicity, effectiveness, and multi-functionality.