Amino‐Functionalized Al<sub>2</sub>O<sub>3</sub> Particles Coating Separator with Excellent Lithium‐Ion Transport Properties for High‐Power Density Lithium‐Ion Batteries
Hui Zhang, Lei Sheng, Yaozong Bai, Shangjun Song, Gaojun Liu, Hairong Xue, Tao Wang, Xianli Huang, Jianping He
Abstract
The coating method of Al 2 O 3 nanoparticles has been widely applied to promote the thermostability and wettability of polyolefin separators. However, the untreated Al 2 O 3 /polyethylene (PE) composite separators still need to improve the ionic conductivity ( σ ) and lithium‐ion transference number ( t Li+ ). Herein, a method is found to obtain amino‐functionalized Al 2 O 3 nanoparticles (N‐Al 2 O 3 ). As a result, the cell with the N‐Al 2 O 3 /PE composite separator has improved σ (0.39 mS cm −1 ) and t Li+ (0.49). The LiCoO 2 /Li half‐cell based on N‐Al 2 O 3 /PE composite separator exhibits higher discharge capacity (125 mAh g −1 ) and better cycle performance under the current density of 1 C. Furthermore, the cell containing N‐Al 2 O 3 /PE composite separator has a better rate performance and the discharge capacity still maintains 75 mAh g −1 at a high rate of 4 C. This method is effective and simple to modify the PE separator with the amino‐functionalized Al 2 O 3 nanoparticles and enhance the high rate performance of Li‐ion batteries.