用于锂离子电池的具有高离子传导率和循环稳定性的纯纤维素纳米纤维隔膜

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

作者信息

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

机构信息

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.

出版信息

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

DOI:10.1016/j.ijbiomac.2023.126078

PMID:37532188

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 LiFePO/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.

摘要

传统聚烯烃隔膜受限于较差的电解液润湿性、较低的热稳定性和低离子电导率，这严重限制了它们在高性能锂离子电池（LIBs）中的应用。在此，以纤维素纳米纤维（CNF）为基质、叔丁醇（TBA）为分散介质，通过简便的过滤方法制备了用于LIBs的纯CNF隔膜。全面研究了干燥温度对隔膜的孔结构、电解液润湿性、机械性能、热稳定性和离子电导率的影响。结果表明，以TBA为分散介质在-80°C下冷冻干燥的隔膜（TBA-FD）具有最佳的综合性能，孔隙率和电解液吸收率分别高达70.8%和296%，离子电导率高达1.90 mS/cm。CNF隔膜在160°C时无明显热收缩，显示出良好的热稳定性。此外，用TBA-HD（叔丁醇作为分散介质在80°C下热干燥）和TBA-FD隔膜组装的LiFePO/锂金属电池表现出优异的循环稳定性（容量保持率分别高达97.5%和96.4%）和倍率性能。通过简便方法制备的具有良好性能的纯CNF隔膜在高性能LIBs方面极具前景。