中国物理B ›› 2016, Vol. 25 ›› Issue (1): 16101-016101.doi: 10.1088/1674-1056/25/1/016101
• SPECIAL TOPIC—Fundamental physics research in lithium batteries • 上一篇 下一篇
Liumin Suo(索鎏敏), Zheng Fang(方铮), Yong-Sheng Hu(胡勇胜), Liquan Chen(陈立泉)
Liumin Suo(索鎏敏), Zheng Fang(方铮), Yong-Sheng Hu(胡勇胜), Liquan Chen(陈立泉)
摘要: Cation-anion interaction with different ratios of salt to solvent is investigated by FT-Raman spectroscopy. The fitting result of the C-N-C bending vibration manifests that the cation-anion coordination structure changes tremendously with the variation of salt concentration. It is well known that lithium-ion transport in ultrahigh salt concentration electrolyte is dramatically different from that in dilute electrolyte, due to high viscosity and strong cation-anion interaction. In ultrahigh salt concentrated “solvent-in-salt” electrolyte (SIS-7#), we found, on one hand, that the cation and anion in the solution mainly formed cation-anion pairs with a high Li+ coordination number ( ≥ 1), including intimate ion pairs (20.1%) and aggregated ion pairs (79.9%), which not only cause low total ionic conductivity but also cause a high lithium transference number (0.73). A possible lithium transport mechanism is proposed: in solvent-in-salt electrolytes, lithium ions' direct movement presumably depends on Li-ion exchange between aggregated ion pairs and solvent molecules, which repeats a dissolving and re-complexing process between different oxygen groups of solvent molecules.
中图分类号: (Techniques for structure determination)