Pure cellulose nanofiber separator with high ionic conductivity and cycling stability for lithium-ion batteries

Nan Wang; Wenyong Liu; Haiyang Liao; Zhihan Li; Yi Chen; Guangsheng Zeng

doi:10.1016/j.ijbiomac.2023.126078

Pure cellulose nanofiber separator with high ionic conductivity and cycling stability for lithium-ion batteries

Int J Biol Macromol. 2023 Oct 1:250:126078. doi: 10.1016/j.ijbiomac.2023.126078. Epub 2023 Aug 1.

Authors

Nan Wang¹, Wenyong Liu², Haiyang Liao³, Zhihan Li¹, Yi Chen¹, Guangsheng Zeng³

Affiliations

¹ Hunan Key Laboratory of Biomass Fiber Functional Materials, Hunan International Scientific and Technological Innovation Cooperation Base of Biomass Fiber Materials and Application, Hunan University of Technology, Zhuzhou 412007, China; National and Local Joint Engineering Research Center of Advanced Packaging Materials Research and Development Technology, Hunan Key Laboratory of Advanced Packaging Materials and Technology, College of Packaging and Material Engineering, Hunan University of Technology, Zhuzhou 412007, China.
² Hunan Key Laboratory of Biomass Fiber Functional Materials, Hunan International Scientific and Technological Innovation Cooperation Base of Biomass Fiber Materials and Application, Hunan University of Technology, Zhuzhou 412007, China; National and Local Joint Engineering Research Center of Advanced Packaging Materials Research and Development Technology, Hunan Key Laboratory of Advanced Packaging Materials and Technology, College of Packaging and Material Engineering, Hunan University of Technology, Zhuzhou 412007, China. Electronic address: liuwenyong@hut.edu.cn.
³ Hunan Key Laboratory of Biomass Fiber Functional Materials, Hunan International Scientific and Technological Innovation Cooperation Base of Biomass Fiber Materials and Application, Hunan University of Technology, Zhuzhou 412007, China.

PMID: 37532188
DOI: 10.1016/j.ijbiomac.2023.126078

Abstract

Conventional polyolefin separators are constrained by poor electrolyte wettability, inferior thermal stability, and low ionic conductivity, which seriously restrict their application in high-performance lithium-ion batteries (LIBs). Herein, cellulose nanofiber (CNF) as the matrix and tert-butyl alcohol (TBA) as the dispersion medium were used to prepare the pure CNF separators for LIBs by a facile filtration method. The effects of the drying temperature on the pore structure, electrolyte wettability, mechanical properties, thermal stability, and ionic conductivity of the separators were comprehensively investigated. The results showed that the freeze-dried separator at -80 °C with TBA as the dispersion medium (TBA-FD) had the best overall performance, with the porosity and electrolyte uptake up to 70.8 % and 296 %, respectively, as well as the ionic conductivity up to 1.90 mS/cm. The CNF separators had no apparent thermal shrinkage at 160 °C, illustrating good thermal stability. Moreover, the LiFePO₄/lithium metal battery assembled with the TBA-HD (tert-butyl alcohol as the dispersion medium for heat-drying at 80 °C) and TBA-FD separators displayed superior cycling stability (with a capacity retention rate up to 97.5 % and 96.4 %, respectively) and rate performance. The pure CNF separators with good performance prepared by the facile method are greatly promising for high-performance LIBs.

Keywords: Cellulose nanofiber; Lithium-ion battery; Separator.