A Heat-Resistant Poly(oxyphenylene benzimidazole)/Ethyl Cellulose Blended Polymer Membrane for Highly Safe Lithium-Ion Batteries

Qiuyu Chen; Xiaoxi Zuo; Huiying Liang; Tianming Zhu; Yaotang Zhong; Jiansheng Liu; Junmin Nan

doi:10.1021/acsami.9b17374

A Heat-Resistant Poly(oxyphenylene benzimidazole)/Ethyl Cellulose Blended Polymer Membrane for Highly Safe Lithium-Ion Batteries

ACS Appl Mater Interfaces. 2020 Jan 8;12(1):637-645. doi: 10.1021/acsami.9b17374. Epub 2019 Dec 24.

Authors

Qiuyu Chen¹, Xiaoxi Zuo¹, Huiying Liang¹, Tianming Zhu¹, Yaotang Zhong¹, Jiansheng Liu², Junmin Nan¹

Affiliations

¹ School of Chemistry, MOE Key Laboratory of Theoretical Chemistry of Environment, Guangzhou Key Laboratory of Materials for Energy Conversion and Storage , South China Normal University , Guangzhou 510006 , P. R. China.
² Guangzhou Great Power Energy Technology Co., Ltd. , Guangzhou 511483 , P. R. China.

PMID: 31825197
DOI: 10.1021/acsami.9b17374

Abstract

A blended membrane based on poly(oxyphenylene benzimidazole) (PBI) and ethyl cellulose (EC) exhibits heat resistance and good electrochemical performance. The prepared blended polymer gel membranes show no visible dimensional change after being held at 350 °C for 30 min, whereas the polyethylene (PE) separator almost completely melts. In addition to excellent thermal stability, the self-supporting blended membranes also exhibit a uniform thermal distribution during the heating process from 60 to 200 °C. Additionally, the ionic conductivities of the PBI/EC blended membranes with different ratios are 1.24 mS cm^-1 (1:1), 2.58 mS cm^-1 (1:2), and 1.68 mS cm^-1 (1:3), which are much higher than those of the PE separator (0.39 mS cm^-1). Compared to that of the PE separator (113 mAh g^-1), the cell with a separator of PBI/EC = 1:2 retained a discharge capacity of 131 mAh g^-1 after 150 cycles at 0.5C. Meanwhile, the rate performance of the cell was also better than that of the PE separator, especially at high currents (5C). All of the results indicate that this blended polymer gel membrane with good thermal stability is expected to be applied to high-performance lithium-ion batteries.

Keywords: enhanced electrochemical performance; heat resistance; lithium-ion battery; poly(oxyphenylene benzimidazole)/ethyl cellulose; three-dimensional network-like porous structure.