Multifunctional separators with high safety and regulated ion transport for lithium-ion batteries

• Published in: Journal of power sources 2025-01, Vol.626, p.235794, Article 235794
• Main Authors: He, Xinhua, Wang, Jirong, Zhong, Xiaoqiu, Zhang, Fangqing, Shao, Zhu-Bao, Wang, Yu-Zhong
• Format: Article
• Language: English
• Subjects: Dendrite inhibition; Lithium batteries; Prelithiation; Separator; Thermal safety
• ISSN: 0378-7753
• DOI: 10.1016/j.jpowsour.2024.235794

Poor electrolyte wettability, nasty heat shrinkage and severe dendrite-growth issues of commonly used polyolefin separators significantly hamper further application and improvement of energy-density for lithium-ion batteries (LIBs). Hence, designing and constructing advanced separator materials with good wettability, robust mechanical strength and satisfied fire-thermal safety is critical for next-generation LIBs. In this study, novel separators consisted of bacterial cellulose (BC) and the prelithiated halloysite nanotubes (Li-HNTs), denoted Li-HNTs@BC separator, are designed and prepared via vacuum-assisted strategy. Compared with conventional Celgard separator, the obtained Li-HNTs@BC separators deliver good thermal stability, high porosity (62.99 %) and electrolyte uptake (497 %), and excellent thermal dimensional stability (almost no shrinkage at 300 °C for 30 min). In addition, Li-HNTs could provide extra lithium ions source and expedite lithium ion's migration, thus decreasing the concentration polarization and uneven lithium deposition during the battery cycling. As a result, the assembled Li//LiFePO4 cell using Li-HNTs@BC separator displays obviously improved charging-discharging reversibility and excellent rate capability. More importantly, the separator endows the battery with excellent thermal safety, which could also well-process at 150 °C. [Display omitted] •A multifunctional and organic-inorganic composited separator is developed.•The composited separator exhibits good wettability and excellent thermal dimensional stability at 300 °C.•The prelithiation of inorganic component decreases the concentration polarization and suppress the lithium dendrite.