The continuously increasing number and size of lithium-based batteries developed for large-scale applications raise serious environmental concerns. Herein, we address the issues related to electrolyte toxicity and safety by proposing a “water-in-ionomer” type of electrolyte which replaces organic solvents by water and expensive and toxic fluorinated lithium salts by a non-fluorinated, inexpensive and non-toxic superabsorbing ionomer, lithium polyacrylate. Interestingly, the electrochemical stability window of this electrolyte is extended greatly, even for high water contents. Particularly, the gel with 50 wt% ionomer exhibits an electrochemical stability window of 2.6 V vs. platinum and a conductivity of 6.5 mS cm−1 at 20 °C. Structural investigations suggest that the electrolytes locally self-organize and most likely switch local structures with the change of water content, leading to a 50% gel with good conductivity and elastic properties. A LiTi2(PO4)3/LiMn2O4 lithium-ion cell incorporating this electrolyte provided an average discharge voltage > 1.5 V and a specific energy of 77 Wh kg−1, while for an alternative cell chemistry, i.e., TiO2/LiMn2O4, a further enhanced average output voltage of 2.1 V and an initial specific energy of 124.2 Wh kg−1 are achieved.
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机译:为大规模应用而开发的锂基电池的数量和尺寸的不断增加引起了严重的环境问题。在这里,我们通过提出一种“离聚物水”型电解质来解决与电解质毒性和安全性有关的问题,该电解质可以用水代替有机溶剂,并通过非氟化,廉价且无毒的超吸收剂代替昂贵且有毒的氟化锂盐。离聚物,聚丙烯酸锂。有趣的是,即使对于高水含量,该电解质的电化学稳定性窗口也大大延长。尤其是,具有50%(重量)离聚物的凝胶对铂的电化学稳定性窗口为2.6 V,在20°C下的电导率为6.5 mS cm 。结构研究表明,电解质会局部自组织,并且很可能随水含量的变化而改变局部结构,从而导致50%的凝胶具有良好的导电性和弹性。装有这种电解质的LiTi2(PO4)3 / LiMn2O4锂离子电池提供平均放电电压> 1.5 V和比能77 ofWh kg -1 sup>,同时用于替代电池化学,即TiO2 / LiMn2O4的平均输出电压进一步提高到2.1 V,初始比能达到124.2 Wh kg -1 sup>。
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