Binder-free SiO2 nanoparticles coated polypropylene separator for high performance lithium-ion battery

Abstract

The separators play a crucial role in lithium-ion batteries as a safety and functional component. In this study, we have prepared SiO₂ nanoparticles by sol-gel method and spun them to polypropylene separators. The effects of different particle sizes on the surface morphology, electrolyte wettability and thermal stability have been researched. The results show that SiO₂ nanoparticles with an approximately size of 50 nm are the most effective in enhancing the performance of the separator. Compared to the battery assembled with the unmodified separator, the battery assembled with the composite separator modified by SiO₂ nanoparticles exhibits superior cycling and rate performance. Furthermore, these modified batteries exhibited reduced polarization voltage and impedance under the same current conditions, indicating SiO₂ nanoparticles enhanced interface compatibility between the separator and the electrolyte. This suggests that incorporating SiO₂ nanoparticles into the separator design markedly improves battery performance.