Zhao Kang, Song Hongzan, Duan Xiaoli, Wang Zihao, Liu Jiahang, Ba Xinwu
College of Chemistry & Environmental Science, Hebei University, Baoding 071002, China.
School of Chemistry and Materials Science, Ludong University, Yantai 264025, China.
Polymers (Basel). 2019 Mar 7;11(3):444. doi: 10.3390/polym11030444.
A new family of chemical cross-linked ionogel is successfully synthesized by photopolymerization of hyperbranched aliphatic polyester with acrylate terminal groups in an ionic liquid of 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF₄). The microstructure, viscoelastic behavior, mechanical property thermal stability, and ionic conductivities of the ionogels are investigated systematically. The ionogels exhibit high mechanical strength (up to 1.6 MPa) and high mechanical stability even at temperatures up to 200 °C. It is found to be thermally stable up to 371.3 °C and electrochemically stable above 4.3 V. The obtained ionogels show superior ionic conductivity over a wide temperature range (from 1.2 × 10 S cm at 20 °C up to 5.0 × 10 S cm at 120 °C). Moreover, the Li/LiFePO₄ batteries based on ionogel electrolyte with LiBF₄ show a higher specific capacity of 153.1 mAhg and retain 98.1% after 100 cycles, exhibiting very stable charge/discharge behavior with good cycle performance. This work provides a new method for fabrication of novel advanced gel polymer electrolytes for applications in lithium-ion batteries.
通过在1-丁基-3-甲基咪唑四氟硼酸盐（BMIMBF₄）离子液体中使具有丙烯酸酯端基的超支化脂肪族聚酯光聚合，成功合成了一个新的化学交联离子凝胶家族。系统地研究了离子凝胶的微观结构、粘弹性行为、机械性能、热稳定性和离子电导率。离子凝胶表现出高机械强度（高达1.6 MPa），甚至在高达200℃的温度下也具有高机械稳定性。发现其热稳定性高达371.3℃，电化学稳定性在4.3 V以上。所获得的离子凝胶在很宽的温度范围内显示出优异的离子电导率（从20℃时的1.2×10 S cm到120℃时的5.0×10 S cm）。此外，基于含LiBF₄的离子凝胶电解质的Li/LiFePO₄电池显示出153.1 mAhg的更高比容量，并且在100次循环后保留98.1%，表现出非常稳定的充放电行为和良好的循环性能。这项工作为制备用于锂离子电池的新型先进凝胶聚合物电解质提供了一种新方法。
