Effects of Electrolyte Salts on the Performance of Li鈥揙2 Batteries

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• 作者：Eduard Nasybulin ; Wu Xu ; Mark H. Engelhard ; Zimin Nie ; Sarah D. Burton ; Lelia Cosimbescu ; Mark E. Gross ; Ji-Guang Zhang
• 刊名：The Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：February 14, 2013
• 年：2013
• 卷：117
• 期：6
• 页码：2635-2645
• 全文大小：583K
• 年卷期：v.117,no.6(February 14, 2013)
• ISSN：1932-7455

文摘

The effects of lithium salts on the performance of Li鈥揙₂ batteries and the stability of salt anions in the O₂ atmosphere during discharge/charge processes were systematically investigated by studying seven common lithium salts in tetraglyme as electrolytes for Li鈥揙₂ batteries. The discharge products of Li鈥揙₂ reactions were analyzed by X-ray diffraction, X-ray photoelectron spectroscopy, and nuclear magnetic resonance spectroscopy. The performance of Li鈥揙₂ batteries was strongly affected by the salt used in the electrolyte. Lithium tetrafluoroborate (LiBF₄) and lithium bis(oxalato)borate (LiBOB) decomposed and formed LiF and lithium oxalate, respectively, as well as lithium borates during discharge of Li鈥揙₂ batteries. In the case of other salts, including lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTf), lithium hexafluorophosphate (LiPF₆), lithium perchlorate (LiClO₄), and lithium bromide (LiBr), the discharge products mainly consisted of Li₂O₂ and carbonates with minor signs of decomposition of LiTFSI, LiTf, and LiPF₆. LiBr and LiClO₄ showed the best stability during the discharge process. For the cycling performance, LiTf and LiTFSI were the best among the studied salts. In addition to the instability of lithium salts, decomposition of tetraglyme solvent was a more significant factor contributing to the limited cycling stability. Thus, a more stable nonaqueous electrolyte including organic solvent and lithium salt still needs to be further developed to reach a fully reversible Li鈥揙₂ battery.