Self-Healing fluorinated polymer deep eutectic electrolytes for stable lithium metal batteries

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2024-10, Vol.498, p.155376, Article 155376
• Main Authors: Yu, Yingzhi, Ling, Canhui, Yang, Jixu, Zhu, Antai, Naren, Tuoya, Chen, Yuxin, Chen, Yuejiao, Wei, Weifeng, Ji, Xiaobo, Li, Chengchao, Chen, Libao, Mei, Lin, Kuang, Gui-Chao
• Format: Article
• Language: English
• Subjects: Deep eutectic; Fluorinated gel electrolyte; Lithium metal battery; Self-healing
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2024.155376

[Display omitted] •This work developed a novel fluorinated polymer gel electrolyte (FPDE) containing deep eutectic solvents and self-healing structural unit 2-ureido-4-pyrimidinone.•The fluorinated group endows the electrolyte wide electrochemical window, high migration number and superior interface stability.•Self-healing structural units could alleviate the volumetric expansion of lithium anode during the charging and discharging process, while the deep eutectic solvents make the electrolytes excellent flame-retardant ability.•Symmetric Li||Li cell using the FPDE shows stable performance up to 6000 h. The full cell with Li||FPDE||LFP provides 80.4 % capacity retention after 600 cycles. Lithium metal batteries (LMB) have attracted great attention in the last two decades for their high theoretical capacity and ultralow redox potential. However, LMB commercial applications still face safety risks such as electrolyte leakage, short circuits and even spontaneous combustion. Fluorinated polymer electrolytes have the advantages of high thermal stability and wide electrochemical window, endowing them an ideal alternative to liquid electrolytes. This work draws inspiration from the self-healing mechanism by introducing 2-ureido-4-pyrimidinone (UPy) units and successfully demonstrates that the fluorinated polymer deep eutectic electrolytes (FPDE) show high electrochemical performances in LMB. Self-healing structural units can alleviate the volumetric expansion of lithium anode during the charging and discharging process, while the fluorinated group endow the electrolyte wide electrochemical window, high migration number and superior interface stability. The joint effect of deep eutectic electrolytes and fluoroalkane makes FPDE show excellent flame-retardant performance with 0 s self-extinguish time. Symmetric Li||Li cell using the FPDE shows stable performance up to 6000 h. The full cell with Li||FPDE||LFP provides 80.4 % capacity retention after 600 cycles. This work might show some potential for development high safety LMBs.