High-stability core-shell structured PAN/PVDF nanofiber separator with excellent lithium-ion transport property for lithium-based battery

Xingxu Gao; Lei Sheng; Ling Yang; Xin Xie; Datuan Li; Yun Gong; Min Cao; Yaozong Bai; Haoyu Dong; Gaojun Liu; Tao Wang; Xianli Huang; Jianping He

doi:10.1016/j.jcis.2023.01.033

High-stability core-shell structured PAN/PVDF nanofiber separator with excellent lithium-ion transport property for lithium-based battery

J Colloid Interface Sci. 2023 Apr 15:636:317-327. doi: 10.1016/j.jcis.2023.01.033. Epub 2023 Jan 7.

Authors

Xingxu Gao¹, Lei Sheng¹, Ling Yang¹, Xin Xie¹, Datuan Li¹, Yun Gong¹, Min Cao¹, Yaozong Bai², Haoyu Dong², Gaojun Liu², Tao Wang¹, Xianli Huang¹, Jianping He³

Affiliations

¹ College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, 210016 Nanjing, Jiangsu Province, China.
² Sinoma Lithium Battery Separator Co. Ltd, 277500 ZaoZhuang, Shandong Province, China.
³ College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, 210016 Nanjing, Jiangsu Province, China. Electronic address: jianph@nuaa.edu.cn.

PMID: 36638571
DOI: 10.1016/j.jcis.2023.01.033

Abstract

The ion transport channel constructed by the separator is crucial for the practical performance of Li-ion batteries, including cycling stability and high rate capability under high current. Traditional polyolefin separator is the storage of electrolyte, which guarantees the internal ion transport process. However, its weak interaction with electrolyte and low cationic transport capacity limit the application of lithium ion battery in large current. In this study, a kind of core-shell structured polyacrylonitrile (PAN)/polyvinylidene fluoride (PVDF) nanofiber separator composed of PAN core and PVDF shell was prepared by coaxial electrospinning technique. As a result, the mechanical strength of PAN/PVDF nanofiber separator is increased from 0.6 MPa of PVDF to 3.6 MPa for PAN core. Furthermore, PAN/PVDF nanofiber separator exhibits an improved lithium-ion transference number (0.66), which is resulted from F functional groups of PVDF shell. It is believed that the interactions between the lithium ion and F functional group could construct a fast ion transport channel. The LiCoO₂/Li half-cells assembled with PAN/PVDF exhibited higher discharge capacity (5C) than those cells using pristine PVDF, PAN separators and polyethylene (PE) separator. It is worth mentioning that the cells with PAN/PVDF separator also have excellent cycle stability. This study provides a new idea about separator-design strategy for high-performance lithium-based battery.

Keywords: Core–shell structure; Mechanical properties; PAN; PVDF; Separator.