High‐Performance Al<sub>2</sub>O<sub>3</sub>/PAALi Composite Separator Prepared by Water‐Based Slurry for High‐Power Density Lithium‐Based Battery
Rong Xu, Lei Sheng, Hao Gong, Yulong Kong, Yang Yang, Menglin Li, Yaozong Bai, Shangjun Song, Gaojun Liu, Tao Wang, Xianli Huang, Jianping He
Abstract
The ceramic composite separator shows great thermal stability and electrolyte wettability compared with polyolefin separator, which is applied in the supply source of electric vehicles. However, the preparation of ceramic composite separator is involved with large amount of organic solvents, and it is of great harm to health. Herein, lithium polyacrylate (PAALi) is selected as a novel binder to prepare the Al 2 O 3 /PAALi ceramic composite separator by water‐based slurry. The production of Al 2 O 3 /PAALi composite separator is more environmental‐friendly, and it also exhibits excellent thermal stability. In addition, the Al 2 O 3 /PAALi composite separator has obviously improved lithium transference number of 0.41, compared with polyethylene (PE) separator and Al 2 O 3 /polyvinylidene fluoride (PVDF) composite separator. It can be attributed to the fact that PAALi with a lot of carboxyl (COO − ) functional groups has an interaction with ions and facilitates the desolvation of cation. As a result, the LiCoO 2 /Li half cell using Al 2 O 3 /PAALi composite separator shows higher discharge capacity retention (88%) after 180 cycles and excellent cycling stability. Fortunately, these cells containing Al 2 O 3 /PAALi composite separator also have wonderful rate performance; even at 5 C, the discharge capacity retention still keeps 58%, higher than Al 2 O 3 /PVDF composite separator. Therefore, this is a promising method to further enhance the battery performance.