SnO 2 Functionalized Polyethylene Separator with Enhanced Thermal Stability for High Performance Lithium Ion Battery

Improving the thermal stability and electrolyte affinity of the separator is critical for enhancing the performance of lithium ion batteries. A novel SnO 2 nanoparticle functionalized polyethylene separator prepared through a facile blade coating process is reported. The SnO 2 functionalization effectively enhances the thermal stability of the separator. The functionalized separator could withstand a temperature up to 130 °C. In addition, the novel separator shows significantly improved electrochemical performance due to its good compatibility of the SnO 2 layer with the electrolyte. As a result of these favourable features, the SnO 2 functionalized separator presents excellent battery performance. The discharge capacity of the LiCoO 2 half‐cell with the functionalized separator at 5C is improved by ∼13% at room temperature. Besides, the functionalized separator also exhibits superior discharge performance at 80 °C. These results demonstrate the high potential of the SnO 2 functionalized separator for practical lithium ion battery applications.