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化学学报
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化学学报 ›› 2009, Vol. 67 ›› Issue (21): 2395-2401.    下一篇

研究论文

金属锂在含(亚)硫酰基添加剂电解液中电化学可逆性研究

刘思思     杨军*     王飞     努丽燕娜     王久林   

  1. (上海交通大学化学化工学院 上海 200240)
  • 投稿日期:2009-03-31 修回日期:2009-05-25 发布日期:2009-07-06
  • 通讯作者: 杨军 E-mail:yangj723@sjtu.edu.cn

Electrochemical Reversibility of Li Metal in Electrolytes Containing Sulfinyl or Sulfuryl Additives

Liu, Sisi ;Yang, Jun* ;Wang, Fei ;Nuli, Yanna; Wang, Jiulin   

  1. (School of Chemistry and Chemical Engineering, Shanghai Jiaotong University, Shanghai 200240)
  • Received:2009-03-31 Revised:2009-05-25 Published:2009-07-06

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分别以亚硫酰氯(SOCl2)、硫酰氯(SO2Cl2)、二甲亚砜(DMSO)、苯磺酰氯(BSC)和苯基乙烯基亚砜(PVSO)作为添加剂, 加入至1 mol•L－1 LiPF6/碳酸乙烯酯(EC)＋碳酸二甲酯(DMC)(体积比为1∶1)电解液中, 采用恒电流沉积-溶出法、循环伏安法(CV)、电化学阻抗谱(EIS)、X射线光电子能谱(XPS)测试技术, 研究了添加剂对电化学金属锂沉积-溶出可逆性以及金属锂负极/电解液界面性质的影响. 电化学测试结果表明, 添加SO2Cl2和BSC能显著改善金属锂电极的循环性能, 100% DOD(锂全溶出)条件下, 循环效率稳定在90%左右. 电化学测试、添加剂分子电子亲和能计算并结合XPS测试结果表明, 较早反应成膜的SO2Cl2和BSC添加剂可以在一定程度上抑制电解液溶剂的分解, 使锂电极循环效率和寿命得以提高. 洞察和比较添加剂的结构揭示, 含磺酰基的化合物明显优于含亚磺酰基的化合物.

关键词: (亚)硫酰基, 添加剂, 二次锂电池, 锂电极, 电化学可逆性

Thionyl chloride (SOCl2), sulfuryl chloride (SO2Cl2), dimethyl sulfoxide (DMSO), benzenesulfonyl chloride (BSC) and phenyl vinyl sulfoxide (PVSO) were used as electrolyte additives in 1 mol•L－1 LiPF6-EC/DMC to examine the electrochemical reversibility of lithium deposition-dissolution and the influence on the interface property between lithium metal anode and the electrolyte. The related research tools and methods include constant current deposition and dissolution, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS). The electrochemical test results indicate that SO2Cl2 and BSC additives can remarkably improve the cycling performance of lithium metal anode. The cycling efficiency is stabilized at 90% under 100% DOD (complete deposition-dissolution). Electrochemical tests, in combination with calculation of electron affinities and XPS results, reveal that a preferential filming reaction of SO2Cl2 with BSC can suppress the electrolyte decomposition and improve the cycling efficiency and life-span of the lithium anode. Judged from the additive structures, sulfuryl compounds are superior over sulfinyl ones.

Key words: sulfinyl and sulfuryl compound, additive, rechargeable lithium battery, lithium metal anode, electrochemical reversibility