Ultrathin MgB2 nanosheet-modified polypropylene separator for high-efficiency lithium-sulfur batteries

Yong-Chao Zhang; Yan-Wei Li; Caidi Han; Yingtai Qin; Jinhao Zhang; Jinting Wu; Jian Gao; Xiao-Dong Zhu

doi:10.1016/j.jcis.2023.08.193

Ultrathin MgB₂ nanosheet-modified polypropylene separator for high-efficiency lithium-sulfur batteries

J Colloid Interface Sci. 2024 Jan;653(Pt A):664-672. doi: 10.1016/j.jcis.2023.08.193. Epub 2023 Sep 1.

Authors

Yong-Chao Zhang¹, Yan-Wei Li², Caidi Han³, Yingtai Qin³, Jinhao Zhang³, Jinting Wu³, Jian Gao³, Xiao-Dong Zhu⁴

Affiliations

¹ State Key Laboratory Base of Eco-Chemical Engineering College of Chemical Engineering, Qingdao University of Science & Technology, Qingdao 266042, China; Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Nankai University, Tianjin 300071, China.
² Guangxi Key Laboratory of Electrochemical and Magneto-chemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541006, China.
³ State Key Laboratory Base of Eco-Chemical Engineering College of Chemical Engineering, Qingdao University of Science & Technology, Qingdao 266042, China.
⁴ Guangxi Key Laboratory of Electrochemical and Magneto-chemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541006, China; State Key Laboratory Base of Eco-Chemical Engineering College of Chemical Engineering, Qingdao University of Science & Technology, Qingdao 266042, China. Electronic address: xiao-dong_zhu@qust.edu.cn.

PMID: 37741174
DOI: 10.1016/j.jcis.2023.08.193

Abstract

The separator is an important component in lithium-sulfur (Li-S) batteries. However, the conventional polypropylene (PP) separators have the problem of easy shuttling of lithium polysulfide (LiPSs). Herein, ultrathin magnesium boride (MgB₂) nanosheets were prepared by ultrasonic-assisted exfoliation technology, and were suction-filtered onto a separator to serve as a separator modification layer. The introduction of a microporous structure into MgB₂ nanosheets after ultrasonic peeling increases the specific surface area and pore volume, with more adsorption sites, which can fully utilize the surface adsorption/catalytic performance of MgB₂ for LiPSs and accommodate the volume expansion of lithium sulfide (Li₂S). Therefore, MgB₂@PP as a separator significantly improves the sulfur utilization and cycle stability in Li-S batteries. When the MgB₂@PP separator is used, the reversible specific capacity of the assembled Li-S battery at 0.1 C (current rate) is 1184 mAh/g, and the specific capacity at 2 C is 732 mAh/g. After 500 cycles at 2 C, it remains at 497 mAh/g.

Keywords: Li-S batteries; MgB(2) nanosheets; Separator modification layer; Suppressing shuttle effect.