The high performances of SiO2/Al2O3-coated electrospun polyimide fibrous separator for lithium-ion battery.

A SiO 2 /Al 2 O 3 -coated electrospun PI membrane was prepared by means of simple dip coating of Al 2 O 3 and SiO 2 mixture onto electrospun PI membrane. The electrochemical performance of the membrane was tested as a separator in the lithium-ion batteries and compared with those of PI membrane, Al 2 O 3 -coated PI membrane, SiO 2 -coated PI membrane, trilayer SiO 2 /Al 2 O 3 -coated PI membraneand Celgard 2400 separators. The SiO 2 /Al 2 O 3 -coated electrospun PI membrane exhibits the best electrochemical performance, including the cycling performance and rate capability. The optical mass ratio of SiO 2 /Al 2 O 3 was 2:1. The SiO 2 component on the interface decrease the interface resistance. Meanwhile, Al 2 O 3 component increase the ionic conductivity. Owing to the intrinsic thermal stability of ceramic materials and PI, the composite membrane doesn’t have the thermal shrinkage problem of commercial separators. [ABSTRACT FROM AUTHOR]